Can't paint 910 Medina Studio

Saw this post and thought it might be referring to wall patterns.  It doesn't, but since I was testing anyway, I went to 910 Medina Studio, bought an easel (cheapest one), placed it in the bedroom, and sent the sim to paint.  He was able to do so without any issues.  Have you tried this in a brand-new save, without making any alterations to the apartment and with the original sim living in it?  If that works, then I'd be asking about what changes you might have made to the apartment in build/buy and if you moved different sims into it.