We started getting this error a few weeks ago. We are on version 2019.4.2
System.ArgumentException
at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at Octopus.Core.PackageMetadata.PackageMetadataCleaner.<>c.<Execute>b__6_2(IGrouping`2 packageReferenceGroup)
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at Octopus.Core.PackageMetadata.PackageMetadataCleaner.Execute(ICollection`1 packagesUsedByReleases, CancellationToken cancellationToken)
at Octopus.Server.Orchestration.ServerTasks.ApplyRetentionPolicies.ApplyRetentionPoliciesTaskController.ApplyPackageRetention()
at Octopus.Server.Orchestration.ServerTasks.ApplyRetentionPolicies.ApplyRetentionPoliciesTaskController.Execute()
at Octopus.Server.Orchestration.ServerTasks.RunningTask.RunMainThread() ```