IBucket.PingAsync doesn't work with multiple threads

Bucket.PingAsync() doesn't work when called from multiple threads. 

Psedo code:

cluster = Cluster.ConnectAsync(..) 

cluster.PingAsync() 

delay 5 sec 

parallel foreach bucketName in bucketNames 

   bucket = cluster.GetBucketAsync() 

   bucket.PingAsync()

The very first bucket ping succeeds but the following fails, even though the bucket exists.

Parallel code works if you have a cluster per bucket.

First reported on the forums