I’m having this exact problem with a human sim doing the Strangerville Mystery. I might see if this Is aspiration-specific; maybe only base game aspirations work?.
Can't be the base game aspirations that work, because I just found this thread having the same bug with Collector aspiration. I had two sims resolve to lose weight, and it appears to have worked for one and not the other. I've never installed mods or cc. Quite disappointing to achieve a resolution and then not have it counted, in fact get a bad moodlet for it!
Update: I found a workaround to fix the issue. Another year passed, and I had the same problem again, but noticed it's only affecting the resolutions that have to do with aspiration milestones. If you change aspirations and THEN hit a milestone, you will get your resolution finished. I know that may be annoying, but it did work fo rme.
