What do you want fixed the picture is not worth one word Explain.

The paint crumbling at the corners between the trim and tile trim edging. No water runs from the shower door onto the ledge corners. My husband (retired home inspector) said he saw this a lot. If this is a common problem, then there must be a solution for a permanent fix? If you click on the picture to enlarge it, it's easier to see.

Water must be getting out

I think the only fix is to remove it all and replace it. Looks like a build up of caulk and paint.

Is it warped in the center? If your husband is a home inspector, he knows what's causing it.

You have water damage due to something leaking.

A new shower door with a different style door sweep may work. A first rate shower door installer would probably know what to do.

Two contractors have said that the crumbling paint is from condensation and that always happens. Really? Last year the tile on the shower floor around the drain came loose and the grout cracked up. The contractor we hired for the repair said that incompatible parts were used to attach the drain to the pan. He removed and replaced the pan and retiled the floor. That seems all good. Is it possible that water from around the broken grout on the drain seeped into the drywall and wicked up the wall a bit? We also had roof shingles that were improperly installed over the boot flashing for the bathroom vent which is over the left shower wall where the plumbing is. The paint on the inside shower wall over the tile bubbled from what I assumed was caused from a possible leak at the roof vent. I also wonder if water from that leak could have also contributed the problem. My husband removed the wall trim and found rusted nails at that corner but nothing is wet right now. So, I am wondering if this is all old damage from problems that have been corrected. I guess if we spackle and repaint the drywall at the shower corners we will know if the problem is solved. If drywall walls around shower doors cause a persistent problem my only other thought is that we should tile these walls. Thoughts?

I would say a complete gut job is in order too much leakage from different places to even begin to patch sometihing without knowing what is going on and For your own peace of mind as to mold growth .

I have never had this happen on a shower door.

From the info added after the initial post, this looks like a case where an in-person inspection is really needed. Piecemeal fixes are not working on your shower.

Since you have already had issues with the tile floor failing and the obvious water leaking out at the door, it is time for a complete gut and redo by someone who knows what they are doing. You will have a moldy mess behind all that as the water leaks for quite a while normally before it shows itself.

If that is a door opening for a shower I would say the shower itself isn't properly waterproofed.