Random sims keep flirting with the bartenders in some community lots even though they rarely interact with them. And at one point, one premade sim tried to kiss my own sim but failed, and they barely knew each other. It's really bizarre. I thought maybe it was because I downloaded the "dramafix" mod, but after removing it from my mod folder, there are still sims attempting to flirt with the NPCs and my sims. One even tried purposing even though she's married. Could it be a mod or custom content that's making that issue?

You're probably using the keg mod. For some reason, the person who made it thought it should make sims do completely random social interactions with random sims.

The same thing also happens with Actual Alcohol mod https://modthesims.info/d/676474/ac...-act-drunk.html
The list of random interactions includes: Argue, Fight, Folk song, Squeeze, Smooch, Propose Engagement, Sweet Talk, Tell Dirty Joke.
If you are using ACR, that obviously can also cause random flirting. Bartenders are totally safe NPC-s BTW, there is nothing wrong with interacting with them...