Deployment script generator - not opened

When I try to open Deployment script generator in Architect 2020.1.1115 I get an error

What is wrong? Any advice please?

Maybe you have an index with a duplicate name?

I checked that and it seems there is no two same name indexes on ProjectTask entity or even in SQL database.

Stack trace is:

Stack trace

at System.Collections.Hashtable.Insert(Object key, Object nvalue, Boolean add)
at System.Collections.Hashtable.Add(Object key, Object value)
at Origam.DA.Service.MsSqlDataService.GetSchemaIndexListGenerate(ArrayList schemaTables, Hashtable dbTableList, Hashtable schemaIndexListAll) in d:\a\1\s\Origam.DA.Service\MsSqlDataService.cs:line 521
at Origam.DA.Service.AbstractSqlDataService.CompareSchema(IPersistenceProvider provider) in d:\a\1\s\Origam.DA.Service\AbstractSqlDataService.cs:line 1720
at OrigamArchitect.SchemaCompareEditor.DisplayResults() in d:\a\1\s\OrigamArchitect\SchemaCompareEditor.cs:line 405
at OrigamArchitect.SchemaCompareEditor.CboDatabaseType_SelectedIndexChanged(Object sender, EventArgs e) in d:\a\1\s\OrigamArchitect\SchemaCompareEditor.cs:line 693
at System.Windows.Forms.ComboBox.OnSelectedIndexChanged(EventArgs e)
at System.Windows.Forms.ComboBox.set_SelectedIndex(Int32 value)
at OrigamArchitect.SchemaCompareEditor…ctor() in d:\a\1\s\OrigamArchitect\SchemaCompareEditor.cs:line 50
at OrigamArchitect.Commands.ShowDbCompare.Run() in d:\a\1\s\OrigamArchitect\Commands\Commands.cs:line 694
at OrigamArchitect.frmMain.MenuItemClick(Object sender, EventArgs e) in d:\a\1\s\OrigamArchitect\ArchitectWorkbench.cs:line 1187

I also checked all deployment scripts I used lately and none of them has anything to do with ProjectTask indexes.