Thank you all. OP here - I meant to post this on special needs but I have gotten good feedback. Thankfully, we are seeing a developmental pediatrician tomorrow and I will bring this up, as well as the possibility of a language impairment. There’s a possibility she is very high functioning ASD, but that wouldn’t necessarily explain this either.

Is she at a school with many English Language Learners or in classes with kids who struggle with grammar? If she hears others saying "catched" instead of "caught" or "beated" instead of "beat", it reinforces her errors.
I would really work on irregular verbs at home and always correct her and make her correctly repeat the correct conjugation of the verb.
I would really, really work on this at home and/or get a tutor to practice this. It will immediately effect how people treat her in the future if she is making these mistakes.