MarkMappingOffline hangs until timeout

In version 1.3.3 MarkMappingOffline just hangs until timeout exception occurs. When downgrading to 1.3.2 it works as expected.

Here is a stacktrace dump:
at Microsoft.Azure.SqlDatabase.ElasticScale.ShardManagement.StoreOperation.Do()
at Microsoft.Azure.SqlDatabase.ElasticScale.ShardManagement.BaseShardMapper.Update[TMapping,TUpdate,TStatus](TMapping currentMapping, TUpdate update, Func`4 constructMapping, Func`2 statusAsInt, Func`2 intAsStatus, Guid lockOwnerId)
at Microsoft.Azure.SqlDatabase.ElasticScale.ShardManagement.ListShardMapper`1.Update(PointMapping`1 currentMapping, PointMappingUpdate update, Guid lockOwnerId)
at Microsoft.Azure.SqlDatabase.ElasticScale.ShardManagement.BaseShardMapper.SetStatus[TMapping,TUpdate,TStatus](TMapping mapping, TStatus status, Func`2 getStatus, Func`2 createUpdate, Func`4 runUpdate, Guid lockOwnerId)
at Microsoft.Azure.SqlDatabase.ElasticScale.ShardManagement.ListShardMapper`1.MarkMappingOffline(PointMapping`1 mapping, Guid lockOwnerId)
at Microsoft.Azure.SqlDatabase.ElasticScale.ShardManagement.ListShardMap`1.MarkMappingOffline(PointMapping`1 mapping)

The report names no file or test; start by reproducing the 1.3.3 regression at ListShardMap.MarkMappingOffline and follow the stacktrace through ListShardMapper.Update, BaseShardMapper.SetStatus, and StoreOperation.Do. Compare the behavior with 1.3.2; done means MarkMappingOffline returns successfully instead of waiting for a timeout.

Written by the indexing model from the issue text.