That looks like the areas where painters 'cut in' with a brush before/after applying paint with a roller. They may have applied the paint with the brush more meavily, making the painted area darker.

That happens with finishes with more gloss than matte or flat.

It could be condensation from excessive moisture in the bathroom.
The moisture might be able to pass through the wall but not the trim because of the different kinds of paint used.

You might need a larger exhaust fan.

Looks like a poor paint job just as handymac suggested.

Looks like poor painting, like failing to mix all the cans together before cutting in.

Thanks for the feedback everyone! We looked more closely and it does look like it is a paint issue.