Comment by acoard

Was this recently?

I forget when, but in last ~3-5yrs, I've noticed iOS seems to handle this. If you leave a device plugged in for a long period you eventually getting a notification saying it's not gonna charge as much, and it caps the max battery to 80%.

Just wondering if your story is before or after that feature.

edit: I googled, it was iOS13, so 2019 - https://support.apple.com/en-ca/HT210512