Sounds like a sealer was not used before the top coats,
Try using a sealer over the old coats before top coating,
But sounds like this might be an ongoing issue.
Big difference between undercoat and undercoat sealer.
This is my thought too. We bought an IP that had a false "office" ceiling installed with fluro inserts, just like in an office..... yuck in a house.
After having spent weeks getting this from "original" to "ready to rent" and having painted the whole house inside, hubby (at about 6pm the Friday before the open house to find a tenant at 10am next morning - and me with little children and a baby) decided to rip out the ugly ceiling. I walked in and nearly cried.
The whole lot was a mass of peeling paint. Now we knew why the old chap who owned it had installed a dropped ceiling. Mum took the kids and we scraped and sanded and painted that ceiling until well into the evening.
I called my husband a few choice names .
We had ongoing issues with that ceiling and I think it probably was never sealed before being painted. It has been sealed now and painted several times. The peeling has stopped but up close it isn't exactly pretty. Being a queenslander and up very high, we can get away with it.
I seem to recall a painter telling us what to use to halt the peeling, but cannot remember what it was. Maybe some sort of etch primer or something???