AUTO-BAN when i finished a match.

Well the problem is:

Every time I finish a game it gives me a 5 minute ban while I´m in the lobby waiting for the next game.

The best thing you can do is to submit a support ticket to 343i.

This is a bug and they want to hear about it. It may take some time to get a response but they will categorize it internally so they have all the reports of the same problem together.