Yes! Below the cabin sole and what passes for a compression post was an iron pipe and flange down to the hull. It rusted and broke, allowing the mast to drop about 1". Not much but it slacked the rig and bulkheads moved below decks. It happened about 45 miles from Dry Tortugas, crossing the Gulf stream. So I tightened the rig a bit, sailed conservatively and eventually made it home a week later.
The repair consisted of removing all trace of the pipe and all. I ground down to fiberglass, and replaced the pipe with a fabricated wooden post (laminated 4X6), It was all soaked in resin and epoxied in position. I had a system of hydraulic jacks and props to jack everything back into position, and lift the bulkhead to get the replacement part installed. While the mast was down I also cut out and replaced the deck core below the mast step. Since then, about 15 years, no more issues.
I take it you have had some issues as well?