Missing spells after login

Every time I login I find the last spell slot in lv's 2,3,6,7 have been cleared (I only have up to lv 7 so I don't know about 8 or 9 yet). It is always the same  lv's and always the last slot that are cleared. Has anyone else come across this? (Specialist wizard if that makes any difference).

P.S. My Druid character does not have this problem.

Might be due to having bonus slots due to high casting stat from items with casting stat bonus. If its an item that is not always equipped/active upon login.... like a vfx headwear, weapon, staff, ioun stone, etc. If the items bonus lapses (and then comes back) for any reason, bonus slots are cleared.

That's what it was. I had stopped the stones but forgot about my headband. Thanks for the help

Glad it was something simple!