Thanks for the exact error! Definitely not one we want to uphold, diving into settings again… there’s tons of them; sorry for the hassle and thanks for the help fixing this!
Thanks, I tweaked some more things and also asked discourse support to help out on it.
I could not find a limit for “new users in same thread”, so maybe discourse support can help find that one.
The new user => level 1 user is based on “has opened at least 5 topics, has posted 3 messages” etc. I lowered those numbers as well so people should be quicker considered actual users, but still want to find the specific error that you stumbled upon – thanks for reporting!