Sim age bar not progressing, have tried multiple fixes - Help!

Hello, this is my first post here so please forgive me if I do anything incorrectly! 

I am experiencing an issue with a sim downloaded off the gallery where the age bar does not progress on it's own, remaining at the very beginning of the bar as if they have only just aged up. This sim is the only one experiencing the issue, all the other sims in the same save file are progressing as normal. When moving this sim across to another save file to test whether it was only an issue with the previous one, the issue still remained. I had the sim try to blow out candles on a cake but the option for that wasn't even present. Could it be a possibility that the sim is just flat-out broken or corrupted? Previously, the same sim was displaying werewolf traits despite being a non-occult sim- I was eventually able to fix this, but I haven't found a fix with the aging issue. I have tried:

• Editing the age manually in CAS full edit mode (aging them up by one life stage then aging them back down, hoping that it may restart the age bar)
• Removing them from the household by placing them into Not In World, then bringing them back.
• Using MCCC to manually move along the days lived counter. This worked to move it along but it continued to not progress, only just stay at the spot I had manually moved it to.
• Tried to remove weirdo trait, as well as a couple other hidden traits that I thought the sim could possibly have. I could have possibly missed a hidden trait whilst doing this? Though, I have no possible way to find out what the traits could be as the usual mod suggested to find them is currently not working (or at least did not show up in my game), and as said before this is a gallery sim so I am unsure what happened prior to them being uploaded to the gallery.

Additionally, there is no way that this sim is pregnant as they are unable to and this has lasted longer than three in-game days. I hope that there is a fix for this issue. I don't want to restart as I am currently doing a challenge so it would be painful to have to redo everything :(