My understanding of v3 was that it wasn't user login ready. Therefore Formlister wouldn't work when signing in users.
I have done a v2 to v3 update. Implemented pathologics modxapi package in order to get users logged in but alas I've been unsuccessful. Yes, I've had the same message which I think relates to the model parameter in Formlister.
What's your Formlister snippet?
I must say though I'm also confused about it. I know someone has had success but I've yet to see it ☹️. I'm happy to wait for it all to be working as my user update snippet works a treat.