Move Period Dates

Calla • 💍 6 Year Old Twin Boys 👶🏼👶🏼 Baby Girl 8-30-23 👶🏻
I use Glow & ovia. My cycles have been screwy, but I tracked that I did ovulate last week, so I updated it in both apps. 
Somehow, in Glow, it moved my ACTUAL period dates from the last 9 months!!  Luckily I had the actual dates in Ovia to refer to.
I manually went back in Ovia to change them back, but why in the world would this happen?!? 
Has this happened to anyone before?