Are you sure that is tile? Who bought it?

That isn't called bullnose tile, it is a quarter round trim/liner.

From the photo, it looks like someone painted some wood quarter round to match the tile color ... which you could probably get away with, IF it wasn't in a shower!

Tile doesn't peel. That's painted MDF or something. Not an easy fix.

https://www.houzz.com/discussions/6206582/new-tile-trim-peeling

This has come up before.

https://ctasc.com/expert-answers/what-would-cause-porcelain-tile-bullnose-edges-to-peel/

it looks like mold growth too

i really hope your quarter rounds aren't actually wooden

you may want to dig in behind those niches before you do any paintover jobs

It’s definitely not wood. Some type of tile- porcelain maybe? I’m not sure, I’m not in construction or remodeling. The bathroom was done professionally through a local widely known company a few years ago.

Some brands paint the edges of bullnose tiles instead of glazing them. I think that’s what you have…

Found the box… it was a porcelain edge tile made by Emser. Waiting to hear back from manufacturer on any recommendations to remedy the issue.