Sims start to perform musical numbers when assigned to painting (provided Acting skill allows Perform Musical Number). Clearing cache has no effect, only way to prevent so far has been reducing the A...
Ideas
I'm also having this issue and it's very annoying to tell them to do any task that takes time and they break out into singing or doing scenes. My sim will start doing a comedy scene or musical number while uncovering artifacts, cooking, painting, or even just randomly because they're not currently doing something. It only started affecting the family when I added the artistic ideal to the dynasty.
Maybe they should tune down the frequency that your sim should autonomously do encouraged activities from ideals.
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