I have a problem where every Sim in my family has stopped gaining skill points. It happened after one of my Sims got one of the Group Science Project moodlets which caused her to gain skill points really quickly. Only when the moodlet wore off, it caused every Sim in my family to stop building skills. Using the resetSim cheat doesn't help fix the issue either.

Just to be on the safe side, is there any way to delete any skill boosters (minus those associated with lifetime rewards) that may be preventing my Sims from gaining skills?

I believe that any sort of skill boost would be handled through (possibly hidden/invisible) moodlets. Have you tried seeing if it happens to other sims outside the family?

Oh yeah, I forgot to post an update that it has been happening to at least one other Sim from another household as well.