I accidently wiped my site a few days ago, but had a backup
A couple of the minify cache files didn't upload and now I don't appear to be getting any minify errors...
pressing the empty cache button didn't work but perhaps navigating in your FTP client to where it stores the minify cache might help.
If it happens again I'll let you know
This has also fixed the issue with the google crawler returning internal server error 500's