Chiming in! This was formerly under my care.

To confirm the history, the bike came to me with the powder coat on it. My thinking is that the original paint was shot, so the previous owner had it coated and probably gave it the frame saver treatment.

I installed the BB ~2020 and at that time cleaned and greased the threads. I don't remember there being frame saver visible to me, but a handful of years of riding may have loosened things.

It was always stored indoors and never ridden *at* the beach, for what that's worth. I wonder if over time some amount of rust inside the tubes migrated down to the BB.

I never saw a "before" picture of the frame (maybe it was rusted?), but like Jim said, the only spot rust I saw was one of the top tube cable guides. Hoping this frame gets back on the road