going from lich to legend, i ended up stuck with 3 levels of lich after 'completing' the transformation to legend. after returning to drezen to finish my fetch quest to become legendary, i did the quest to settle down my ziggurat. well, those last 3 levels of lich never disappeared allowing me to level up or take a second class, despite having over 4 million xp. i tried respeccing my character at the pathfinder, but after the first level, i noticed 3 mythic levels were required, so i guess - do the ziggurat cleanup before midnight fane or at least before finishing up in drezen. otherwise, you'll not get any benefit. iomedae DID trick me, nocticula was right. i passed about a week at the war-room table to see if a quest would pop up to finish off the last 3 levels. no dice. just bugged.

Path that makes no sense in game where it is all about mythic power. Oh well i can get better results with mods rather than taking this path.

Do your companions also get a level cap of 40 or just the protagonist?

Well, I just discovered quest progression is lost after beating Deskari in Iz. Cutscene in midnight fane no longer activates, and I am left with leftovers of old Mythic path now...

Become legend.

At least testing this in the inevitable excess DLC, the "Bug" regarding caster level doesn't work quite like they say.

I took 20 levels of arcanist, then 1 in fighter, then 10 in eldritch knight, then 9 in dragon disciple.

What happened was after i reached 28 caster level the game just weirdly rolled over and i had a 2nd separate spellbook for 6 levels. Now maybe thats just a weird interaction between dragon disciple and arcanist, but i didn't need to take it in the order this suggests at least.

Which i believe the cap at 28 is a hard cap, because at least from eldritch knight i should've had 29 (as 9 levels progress casting and i was already 20th level), and this rollover to a new spellbook didn't seem to occur until i took the dragon disciple levels.