De-Aging

Hey all! I’m fairly new to the Sims, so sorry if this question has already been asked, I couldn’t find a solution anywhere. Yesterday my first Sim’s husband aged up into an elder, then shortly after aged down twice into a young adult. And then today her daughter’s wife aged up into an adult then down into a young adult. Is this a known issue, and if so do you have any advice to solve? I’ve tried using the Repair tool on the EA app, and would rather avoid using cheats in case I mess things up further. I’m playing with aging on, no mods, and normal lifespans if that makes a difference. Thank you!