Seems the connectivity between your CD servers and the xConnect server was not stable. Maybe when a website was running and sending the information to xConnect from which CD servers didn't receive the response in a timely manner.
It doesn't mean the xConnect getting any problems or errors.
If your xConnect is hosted under IIS in a separate application, you can try to look at its App Pool settings. Try to change the Start Mode to AlwaysRunning and Idle-timeout Action to Suspend. This can prevent IIS from terminating the xConnect when it reaches the Idle-timeout (20 minutes as default).
