ok, i saw now. This information seems a bit too hidden to me.
Not to mention that it is also wrong (former magic armor), but I could also say mage hand which should last a minute, but actually we don't know exactly when this will disappear. The duration of the spells is incorrect and I think it should be revised or calibrated. Magic armor for example cannot last until a long rest. in short, I believe that for the casters there are still things to see. If they put a timer or something like that it would be more accurate.
Mage Armor's listed duration by the rules is "8 hours". Having it last until a long rest is completely and totally fine.
Find Familiar by the rules has a cast time of 1 hour. Several spells have cast times of 10 minutes. Nobody sits around the tabletop for one hour in real time waiting for the mage to cast Find Familiar, the DM does a time skip.
This is not an exact 1:1 implementation of the 5e rules with no deviation whatsoever. Several changes are pretty good, like "Speak with Animals" lasting until a long rest unless concentration is broken. That sort of thing.