It can be a driver issue, when driver crashes when you closing claymore window, teamviewer lost visual connection. Nvidia have a feature that gpu memory frequency can jump up or down when gpu change pstate. So try lower memory frequency or test without oc
Or, when Claymore miner closes the system restarts, teamviewer will lost connection
Possibilities are driver / clock issues
@OP,
What are your cards, OS and driver installed, are they modded?