We are not aware of an issue with UC 'shutting down' a computer. There is a bug logged for UC 'crashing on exit', but it does not affect usage performance, only happens when closing UC.
Computer shutting down would be a more serious issue with your Computer OS / system in general.
The Answers link you mention is for Windows Based computers, not OSX.
I would contact Technical Support and create a ticket for this issue, rather than ask in answers (not the place for technical help).