For Stack Overflow Extras (SOX), a few users and myself have seen our access token being invalidated very often without any apparent reason.

We aren't requesting new tokens (which would invalidate the previous tokens automatically) and aren't manually revoking them either.

Is there any reason why these are being invalidated themselves?

Also, is there a way to get multiple access tokens for the same application? Currently, I'm allowing users to paste in access tokens from computers they have the userscript installed on so they only request one.

I can't think of any reason why it should happen. Is this a known bug? Or am I doing something stupid?