My boat washer brought to my attention that I was getting some brown ooze out of the latch for the port cockpit locker. I probed it and found coring. It looked and felt like plywood. Anyhow, I surmised that the bimini tends to drain off right above it and that I had started some core rot via the latching hole. So, I dug out whatever was not solid (which was surprisingly little). I then taped off the area,attached some aluminum foil to make a dish and injected epoxy (Git-Rot). Seems to have done the trick. Oddly, I probed the starboard side and there is no corresponding core, the probe goes right in. Here are a couple of pic's:
) has never seen what you describe on any of my latches on my '97 model. All I ever see is a bit of rust color on the stainless steel itself.