Thanks for the reply!Please upload your ck3 save and converter's log.txt, and I'll try to debug and see what's going on. It's possible HRE breaks apart due to religious issues, because an imperial archduchy is most certainly not a wrong government type to hold the emperorship. Oooor, maybe if you have no heir/female heir and literally every other HRE member is a republic or a theocracy, but that's really unlikely...
How do I upload the log.txt? Where would I find that file?
As per the HRE dissolution:
Catholic Feudal ruler with a male heir with 89 legitimacy and plenty of other feudal statelets that could have become the inheritor. My only titles at the time of conversion were e_hre, d_austria, and the associated county titles. The only thing I could think of as far as a theocracy is that CK3 does treat the player's character as the owner of b_religious holdings with the court chaplain (in my case) as the leasee.