diff --git a/muranorepository/Services/ui_forms/ActiveDirectory.yaml b/muranorepository/Services/ui_forms/ActiveDirectory.yaml
index 4c0d148..10ef1cd 100644
--- a/muranorepository/Services/ui_forms/ActiveDirectory.yaml
+++ b/muranorepository/Services/ui_forms/ActiveDirectory.yaml
@@ -95,7 +95,7 @@ forms:
             css: {all: [muranodashboard/css/support_placeholder.css]}
       validators:
         # if unitNamingPattern is given and dcInstances > 1, then '#' should occur in unitNamingPattern
-        - expr: {YAQL: $.serviceConfiguration.dcInstances < 2 or not $.serviceConfiguration.unitNamingPattern.bool() or ('#' in $.serviceConfiguration.unitNamingPattern)}
+        - expr: {YAQL: $.serviceConfiguration.dcInstances < 2 or not $.serviceConfiguration.unitNamingPattern.bool() or '#' in $.serviceConfiguration.unitNamingPattern}
           message: Incrementation symbol "#" is required in the Hostname template
   - instanceConfiguration:
       fields:
diff --git a/muranorepository/Services/ui_forms/AspNetApp.yaml b/muranorepository/Services/ui_forms/AspNetApp.yaml
index 5e72f70..2e38472 100644
--- a/muranorepository/Services/ui_forms/AspNetApp.yaml
+++ b/muranorepository/Services/ui_forms/AspNetApp.yaml
@@ -75,6 +75,10 @@ forms:
           widgetMedia:
             js: [muranodashboard/js/support_placeholder.js]
             css: {all: [muranodashboard/css/support_placeholder.css]}
+      validators:
+        # if unitNamingPattern is given and dcInstances > 1, then '#' should occur in unitNamingPattern
+        - expr: {YAQL: $.serviceConfiguration.dcInstances < 2 or not $.serviceConfiguration.unitNamingPattern.bool() or '#' in $.serviceConfiguration.unitNamingPattern}
+          message: Incrementation symbol "#" is required in the Hostname template
   - instanceConfiguration:
       fields:
         - name: title
diff --git a/muranorepository/Services/ui_forms/AspNetAppFarm.yaml b/muranorepository/Services/ui_forms/AspNetAppFarm.yaml
index b42972e..151d8a5 100644
--- a/muranorepository/Services/ui_forms/AspNetAppFarm.yaml
+++ b/muranorepository/Services/ui_forms/AspNetAppFarm.yaml
@@ -98,7 +98,7 @@ forms:
             css: {all: [muranodashboard/css/support_placeholder.css]}
       validators:
         # if unitNamingPattern is given and dcInstances > 1, then '#' should occur in unitNamingPattern
-        - expr: {YAQL: not $.serviceConfiguration.unitNamingPattern.bool() or ('#' in $.serviceConfiguration.unitNamingPattern)}
+        - expr: {YAQL: not $.serviceConfiguration.unitNamingPattern.bool() or '#' in $.serviceConfiguration.unitNamingPattern}
           message: Incrementation symbol "#" is required in the Hostname template
   - instanceConfiguration:
       fields:
diff --git a/muranorepository/Services/ui_forms/Demo.yaml b/muranorepository/Services/ui_forms/Demo.yaml
index ca9905c..be0e863 100644
--- a/muranorepository/Services/ui_forms/Demo.yaml
+++ b/muranorepository/Services/ui_forms/Demo.yaml
@@ -48,7 +48,7 @@ forms:
             css: {all: [muranodashboard/css/support_placeholder.css]}
       validators:
         # if unitNamingPattern is given and dcInstances > 1, then '#' should occur in unitNamingPattern
-        - expr: {YAQL: not $.serviceConfiguration.unitNamingPattern.bool() or ('#' in $.serviceConfiguration.unitNamingPattern)}
+        - expr: {YAQL: $.serviceConfiguration.dcInstances < 2 or not $.serviceConfiguration.unitNamingPattern.bool() or '#' in $.serviceConfiguration.unitNamingPattern}
           message: Incrementation symbol "#" is required in the Hostname template
   - instanceConfiguration:
           fields:
diff --git a/muranorepository/Services/ui_forms/LinuxApache.yaml b/muranorepository/Services/ui_forms/LinuxApache.yaml
index e6f3d39..bca0939 100644
--- a/muranorepository/Services/ui_forms/LinuxApache.yaml
+++ b/muranorepository/Services/ui_forms/LinuxApache.yaml
@@ -56,6 +56,10 @@ forms:
           widgetMedia:
             js: [muranodashboard/js/support_placeholder.js]
             css: {all: [muranodashboard/css/support_placeholder.css]}
+      validators:
+        # if unitNamingPattern is given and dcInstances > 1, then '#' should occur in unitNamingPattern
+        - expr: {YAQL: $.serviceConfiguration.dcInstances < 2 or not $.serviceConfiguration.unitNamingPattern.bool() or '#' in $.serviceConfiguration.unitNamingPattern}
+          message: Incrementation symbol "#" is required in the Hostname template
   - instanceConfiguration:
           fields:
             - name: title
diff --git a/muranorepository/Services/ui_forms/LinuxTelnet.yaml b/muranorepository/Services/ui_forms/LinuxTelnet.yaml
index 7c423ef..6c3b901 100644
--- a/muranorepository/Services/ui_forms/LinuxTelnet.yaml
+++ b/muranorepository/Services/ui_forms/LinuxTelnet.yaml
@@ -56,6 +56,10 @@ forms:
           widgetMedia:
             js: [muranodashboard/js/support_placeholder.js]
             css: {all: [muranodashboard/css/support_placeholder.css]}
+      validators:
+        # if unitNamingPattern is given and dcInstances > 1, then '#' should occur in unitNamingPattern
+        - expr: {YAQL: $.serviceConfiguration.dcInstances < 2 or not $.serviceConfiguration.unitNamingPattern.bool() or '#' in $.serviceConfiguration.unitNamingPattern}
+          message: Incrementation symbol "#" is required in the Hostname template
   - instanceConfiguration:
           fields:
             - name: title
diff --git a/muranorepository/Services/ui_forms/MsSqlServer.yaml b/muranorepository/Services/ui_forms/MsSqlServer.yaml
index aef7538..1b8428d 100644
--- a/muranorepository/Services/ui_forms/MsSqlServer.yaml
+++ b/muranorepository/Services/ui_forms/MsSqlServer.yaml
@@ -86,6 +86,10 @@ forms:
           widgetMedia:
             js: [muranodashboard/js/support_placeholder.js]
             css: {all: [muranodashboard/css/support_placeholder.css]}
+      validators:
+        # if unitNamingPattern is given and dcInstances > 1, then '#' should occur in unitNamingPattern
+        - expr: {YAQL: $.serviceConfiguration.dcInstances < 2 or not $.serviceConfiguration.unitNamingPattern.bool() or '#' in $.serviceConfiguration.unitNamingPattern}
+          message: Incrementation symbol "#" is required in the Hostname template
   - instanceConfiguration:
       fields:
         - name: title
diff --git a/muranorepository/Services/ui_forms/WebServer.yaml b/muranorepository/Services/ui_forms/WebServer.yaml
index b9f917e..7503701 100644
--- a/muranorepository/Services/ui_forms/WebServer.yaml
+++ b/muranorepository/Services/ui_forms/WebServer.yaml
@@ -66,6 +66,10 @@ forms:
           widgetMedia:
             js: [muranodashboard/js/support_placeholder.js]
             css: {all: [muranodashboard/css/support_placeholder.css]}
+      validators:
+        # if unitNamingPattern is given and dcInstances > 1, then '#' should occur in unitNamingPattern
+        - expr: {YAQL: $.serviceConfiguration.dcInstances < 2 or not $.serviceConfiguration.unitNamingPattern.bool() or '#' in $.serviceConfiguration.unitNamingPattern}
+          message: Incrementation symbol "#" is required in the Hostname template
   - instanceConfiguration:
       fields:
         - name: title
diff --git a/muranorepository/Services/ui_forms/WebServerFarm.yaml b/muranorepository/Services/ui_forms/WebServerFarm.yaml
index 9d0d654..3bf2f6d 100644
--- a/muranorepository/Services/ui_forms/WebServerFarm.yaml
+++ b/muranorepository/Services/ui_forms/WebServerFarm.yaml
@@ -85,7 +85,7 @@ forms:
             css: {all: [muranodashboard/css/support_placeholder.css]}
       validators:
         # if unitNamingPattern is given and dcInstances > 1, then '#' should occur in unitNamingPattern
-        - expr: {YAQL: not $.serviceConfiguration.unitNamingPattern.bool() or ('#' in $.serviceConfiguration.unitNamingPattern)}
+        - expr: {YAQL: not $.serviceConfiguration.unitNamingPattern.bool() or '#' in $.serviceConfiguration.unitNamingPattern}
           message: Incrementation symbol "#" is required in the Hostname template
   - instanceConfiguration:
       fields: