Obvious stupid question, hope you haven’t answered it elsewhere already. I assume from the lack of an upper limit on the psionic talent die that it can become a d20? "Conversely, if you roll a 1 on your Psionic
Talent die, it increases by one die size after the
roll, up to its starting size"— Dan Dillon is the Least Turnip 👥 (@Dan_Dillon_1) April 15, 2020
The limiter for the upper limit is the size of your current die. It specifically says that every time you roll a 1, it increases the die size up to its starting size.
Pretty sure they specified d12 as the limit. Plus d20s are never really used for anything other than a base roll.
It goes: 1d6 at 3rd, 1d8 at 5th, 1d10 at 11th, and 1d12 at 17th level, no matter your base subclass.