KeyNotFoundException when UseEnhancedDurability is true

..ClientFailure System.Collections.Generic.KeyNotFoundException: The given key was not present in
the dictionary.
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
at Couchbase.Core.Buckets.VBucketKeyMapper.get_Item(Int32 index) in C:\Users\jmorris\repos\couchb
ase-net-client\Src\Couchbase\Core\Buckets\VBucketKeyMapper.cs:line 46
at Couchbase.Core.Buckets.KeySeqnoObserver.<ObserveAsync>d__11.MoveNext() in C:\Users\jmorris\rep
os\couchbase-net-client\Src\Couchbase\Core\Buckets\KeySeqnoObserver.cs:line 212
— End of stack trace from previous location where exception was thrown —
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)

at System.Runtime.CompilerServices.ConfiguredTaskAwaitable`1.ConfiguredTaskAwaiter.GetResult()
at Couchbase.Core.Buckets.CouchbaseRequestExecuter.<SendWithDurabilityAsync>d__10`1.MoveNext() in
C:\Users\jmorris\repos\couchbase-net-client\Src\Couchbase\Core\Buckets\CouchbaseRequestExecuter.cs:
line 358
...ClientFailure System.Collections.Generic.KeyNotFoundException: The given key was not present in t
he dictionary.
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
at Couchbase.Core.Buckets.VBucketKeyMapper.get_Item(Int32 index) in C:\Users\jmorris\repos\couchb
ase-net-client\Src\Couchbase\Core\Buckets\VBucketKeyMapper.cs:line 46
at Couchbase.Core.Buckets.KeySeqnoObserver.<ObserveAsync>d__11.MoveNext() in C:\Users\jmorris\rep
os\couchbase-net-client\Src\Couchbase\Core\Buckets\KeySeqnoObserver.cs:line 212