An item with the same key has already been added

Small logging snippet for oracle schema compare 4.0.0.14

17:40:08.933|Error  |Engine Service      |1  |Exception in progress dialog
System.ArgumentException: An item with the same key has already been added.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at RedGate.Oracle.SchemaCompare.Actions.ActionGenerators.IndexActionGenerator.FindSyncIssues(IEnumerable`1 #tIc, #TED #TsPb)
   at RedGate.Oracle.SchemaCompare.Actions.ActionGenerators.ActionGenerator`1.#OAke(IEnumerable`1 #tIc, #TED #TsPb)
   at RedGate.Oracle.SchemaCompare.Actions.SyncActions.FindSyncIssues()
   at RedGate.Oracle.Compare.EngineController.Schema.ProgressTasks.FindSyncIssuesProgressTask.<>c__DisplayClass0_0.<.ctor>b__0()
   at RedGate.Shared.Controls.ProgressDialogEx.<>c__DisplayClass7.<DoTasks>b__4(Object q)

I'm getting this error on our db schema after deploying a set of tables. Appearantly somebody or something created a double index somehow. The problem is, the tables I'm touching are 100% sure without double named indexes.

Could you help with a trick in finding which index I need to destroy in a short amount of time?

Might even be a good practice for you guys to add the key in the error message, makes it way more user friendly in finding what object is giving this booboo.