and, well, BUG is a strong word for that - Unhappiness!
The starting day of a time condition in Firewall Objects is Sunday.
The starting day of a time for Web Content Filter is Monday.
Unhappy - not more!
I'd have tried to fix it myself, but I still searching for the "onParametersSaved"-function of the ContentFilter.php...or how it otherwise works... :D(well a little bit logic...Modify.php...but I'm still away from changing it my self!)