This afternoon Twitter has reported a log-out issue thanks to a large amount of users reporting problems with their acounts on mobile phones apps.
This issue appears to be based with the ‘signed OAuth requests’ Which involve valid access tokens and these are being responded to with a 401 Unauthorized errors. Hence the Log Out.
The harsh tag for this matter on twitter is: #T4BB
Also twitter users can follow updates on twitters developers website at: http://bbry.lv/zjdByd