Does your Pool Professional have one of these?
C61-883338:  A Contractor's License

What are pop-offs/plaster delamination?

This is essentially when a piece of plaster breaks away from the gunite on the pool floor and causes a form of crater.

In my experience, these occur in pools that have been replastered and that maybe the company didn't prepare the surface as they should before laying the new plaster. What happens is small voids appear beneath the pool's plaster surface, and the voids can be caused for more reasons other than bad preparation such as plaster shrinkage, cracks or even hollow spots between pool fixtures and the plaster.

The result is small bumps/mounds on the pool floor that are now filled with water and if stepped on will break and look like the examples in the pictures shown.

This repair can be carried out underwater, saving you time and expense!