Sim has grouch moodlet without grouch trait

This happens to me when I'm playing a sim who is not a grouch, but talking to a sim who is.

Just go this while/from "Spread Rumors about others..." with my Mischievious Sim.

My sim in the social media career had several sims over, because her work-from-home tasks were "be funny to 5 sims" and "level up writing skill". She was telling jokes to her guests while writing, and sometime during that activity she got the "Is this... Kindness? (from Grouch trait)", but she isn't a grouch. Maybe one of her guests was a grouch, I don't know, but if so, they should have been the one to get the moodlet, not my sim.