But no matter if store as GMT or local the stored time is always the local time.
And the time shown is list view is always the stored time + TZ offset.
E.g. my local time (today UTC + 2) is 16:58
The stored time is always 16:58 (new, edit, store as GMT or store as local)
The time in list is always 18:58
Not sure how this ever worked. @exchudy can you unzip the attached into your joomla root directory. It includes a replacement for the timestamp.php file. Please report back if it is now working for you. @troester if you would do the same please?