Did a re-install, problem no longer occurs.
However, I think I found a bug: when my Bladesinger reaches lvl 9 (as mage), they get an ability to advance weapon proficiency, but they can only select weapons with which the proficiency hasn't been maxed out yet. They're supposed to get an ability which designated a weapon as weapon of choice, granting an extra 0.5 attack per round.
If you install "Move Archer kit to Fighter" and then "Add Elven Archer", there's no Elven Archer under the Ranger kits.
I've also installed the regional Rangers, together with the un-nerfed spell tables for Rangers from Tweaks and at lvl 9, there's still only 1 divine spell slot. (Which appeared at lvl 6.)