Schema class fixed.

src/Squidex.Domain.Apps.Core.Model/Schemas/Schema.cs

@@ -105,6 +105,12 @@ namespace Squidex.Domain.Apps.Core.Schemas
             fieldsOrdered = ImmutableArray.Create(fields);
         }
 
+        protected override void OnCloned()
+        {
+            fieldsById = null;
+            fieldsByName = null;
+        }
+
         [Pure]
         public Schema Update(SchemaProperties newProperties)
         {
@@ -192,7 +198,7 @@ namespace Squidex.Domain.Apps.Core.Schemas
         [Pure]
         public Schema DeleteField(long fieldId)
         {
-            if (!fieldsById.TryGetValue(fieldId, out var field))
+            if (!FieldsById.TryGetValue(fieldId, out var field))
             {
                 return this;
             }

tests/RunCoverage.ps1

@@ -76,6 +76,6 @@ if ($all -Or $users) {
 	-oldStyle
 }
 
-&"$folderHome\.nuget\packages\ReportGenerator\3.0.1\tools\ReportGenerator.exe" `
+&"$folderHome\.nuget\packages\ReportGenerator\3.0.2\tools\ReportGenerator.exe" `
 -reports:"$folderWorking\$folderReports\*.xml" `
 -targetdir:"$folderWorking\$folderReports\Output"