Issue title: Random Authentication Error in Redis
 Issue body: We are facing random authentication error when connecting to Redis cluster
This error is happening very rarely and but becoming an issue.

Redis client: StackExchange.Redis" Version="2.1.58"

We have set ssl=True,sslProtocols=Tls12 and password  in the connection string. The password is set correctly but facing random authentication error.

Exception.
_StackExchange.Redis.RedisConnectionException: It was not possible to connect to the redis server(s). There was an authentication failure; check that passwords (or client certificates) are configured correctly. AuthenticationFailure on master.adminfacade-redis.0hlgd0.euw1.cache.amazonaws.com:7070/Interactive, Initializing/NotStarted, last: NONE, origin: ConnectedAsync, outstanding: 0, last-read: 0s ago, last-write: 0s ago, keep-alive: 60s, state: Connecting, mgr: 10 of 10 available, last-heartbeat: never, global: 76s ago, v: 116.69.203.115321
at StackExchange.Redis.ConnectionMultiplexer.ConnectImplAsync(ConfigurationOptions configuration, TextWriter log) in /_/src/StackExchange.Redis/ConnectionMultiplexer.cs:line 879_

Do you have suggestion on how to find the root-cause of this issue and how to solve it.

 Comments: 
 Comment 0: > We are facing random authentication error when connecting to Redis cluster.
> The redis connection and all the subsequent operations are working perfectly most of the time.
> But then we are having a random authentication error which is happening very rarely.
> 
> Redis client: StackExchange.Redis" Version="2.1.58"
> 
> We have set ssl=True,sslProtocols=Tls12 and password in the connection string. The password is set correctly but facing random authentication error.
> 
> Exception.
> _StackExchange.Redis.RedisConnectionException: It was not possible to connect to the redis server(s). There was an authentication failure; check that passwords (or client certificates) are configured correctly. AuthenticationFailure on Interactive, Initializing/NotStarted, last: NONE, origin: ConnectedAsync, outstanding: 0, last-read: 0s ago, last-write: 0s ago, keep-alive: 60s, state: Connecting, mgr: 10 of 10 available, last-heartbeat: never, global: 76s ago, v: mcdowellmonica@example.net(ConfigurationOptions configuration, TextWriter log) in /_/src/StackExchange.Redis/ConnectionMultiplexer.cs:line 879_
> 
> Do you have suggestion on how to find the root-cause of this issue and how to solve it.


{'source': 'GithubIssues', 'repo_name_with_owner': 'StackExchange/StackExchange.Redis', 'issue_id': 782308010, 'repo_stars': 5666.0}