Hello,
It doesn't look like spell DC isn't showing properly on the character sheet when stat boosting items are used that effect it. If I put on the warped headband of intellect to have Lae'zel's intellect to 18 and load the game, it says I have an int spell DC on eldritch knight of 14 (correct), but if I take the item off the character sheet still says 14 even though when used in combat the correct 10 is used in it's place. Similarly, if I load the game with the item not equip but then put it on, the character sheet will still show a DC of 10, but when using a spell the correct DC of 14 is taken into account in the combat log.
The bug at this point seems purely visible on the character sheet, the spell attack damage does appear to swap the values immediately when the item is put on, just not the spell DC.
Thanks