SQLite error cannot rollback - no transaction is active

Dear all, I try to backup my files from NAS to Onedrive, at the end of one backup job I get the following error message. I tried to start the job again, error message is the same.
Duplicati is running on Ubuntu VM on QNAP.

Is there a hint in the log?:
24. Mrz. 2020 23:44: Failed while executing “Backup” with id: 2
Mono.Data.Sqlite.SqliteException (0x80004005): SQLite error

cannot rollback - no transaction is active
at Mono.Data.Sqlite.SQLite3.Reset (Mono.Data.Sqlite.SqliteStatement stmt) [0x00084] in <9f9e77068b254e31987d78c4f0dba8a7>:0
at Mono.Data.Sqlite.SQLite3.Step (Mono.Data.Sqlite.SqliteStatement stmt) [0x0003d] in <9f9e77068b254e31987d78c4f0dba8a7>:0
at Mono.Data.Sqlite.SqliteDataReader.NextResult () [0x00104] in <9f9e77068b254e31987d78c4f0dba8a7>:0
at Mono.Data.Sqlite.SqliteDataReader…ctor (Mono.Data.Sqlite.SqliteCommand cmd, System.Data.CommandBehavior behave) [0x0004e] in <9f9e77068b254e31987d78c4f0dba8a7>:0
at (wrapper remoting-invoke-with-check) Mono.Data.Sqlite.SqliteDataReader…ctor(Mono.Data.Sqlite.SqliteCommand,System.Data.CommandBehavior)
at Mono.Data.Sqlite.SqliteCommand.ExecuteReader (System.Data.CommandBehavior behavior) [0x00006] in <9f9e77068b254e31987d78c4f0dba8a7>:0
at Mono.Data.Sqlite.SqliteCommand.ExecuteNonQuery () [0x00000] in <9f9e77068b254e31987d78c4f0dba8a7>:0
at Mono.Data.Sqlite.SqliteTransaction.IssueRollback (Mono.Data.Sqlite.SqliteConnection cnn) [0x00012] in <9f9e77068b254e31987d78c4f0dba8a7>:0
at Mono.Data.Sqlite.SqliteTransaction.Rollback () [0x00008] in <9f9e77068b254e31987d78c4f0dba8a7>:0
at Mono.Data.Sqlite.SqliteTransaction.Dispose (System.Boolean disposing) [0x00018] in <9f9e77068b254e31987d78c4f0dba8a7>:0
at System.Data.Common.DbTransaction.Dispose () [0x00000] in <9096cbcbb5f94a78808c67ee94a07cf7>:0
at Duplicati.Library.Main.Database.LocalDatabase.Dispose () [0x0006d] in :0
at Duplicati.Library.Main.Database.LocalBackupDatabase.Dispose () [0x00000] in :0
at Duplicati.Library.Main.Operation.BackupHandler.RunAsync (System.String sources, Duplicati.Library.Utility.IFilter filter, System.Threading.CancellationToken token) [0x010b1] in :0
at CoCoL.ChannelExtensions.WaitForTaskOrThrow (System.Threading.Tasks.Task task) [0x00050] in <9a758ff4db6c48d6b3d4d0e5c2adf6d1>:0
at Duplicati.Library.Main.Operation.BackupHandler.Run (System.String sources, Duplicati.Library.Utility.IFilter filter, System.Threading.CancellationToken token) [0x00009] in :0
at Duplicati.Library.Main.Controller+<>c__DisplayClass14_0.b__0 (Duplicati.Library.Main.BackupResults result) [0x0004b] in :0
at Duplicati.Library.Main.Controller.RunAction[T] (T result, System.String& paths, Duplicati.Library.Utility.IFilter& filter, System.Action`1[T] method) [0x0026f] in :0
at Duplicati.Library.Main.Controller.Backup (System.String inputsources, Duplicati.Library.Utility.IFilter filter) [0x00074] in :0
at Duplicati.Server.Runner.Run (Duplicati.Server.Runner+IRunnerData data, System.Boolean fromQueue) [0x00349] in :0

Additional I installed the new version 2.0.5.104_canary_2020-03-25 as I thought it might help, started the backup again and get at the end of the backup the same error message.