Elder Sim keeps reverting back to Young Adult

I have an elder that keeps visually changing back to a young adult. It even shows young adult on the lifespan tab. However, I when I had him use a birthday cake to age him up to fix the glitch, he’d actually age up two life jumps. The visual glitch jumps back and forth randomly. Seems to happen when different menus pop up-calendar, travel, etc. 

I had deleted all my mods to see if that was the issue and it wasn’t. It continues to do this without mods. 

I play on PC