Still no solution in hand, but the boat is in the yard. Because I am a chicken, I am having my glass guy take a look. The step is loose, and I will post pictures tomorrow.

The post is still in place. I am more convinced than ever that the reason the pad is tabbed to to the cabin ceiling is because the post was inserted before the cabin top deck structure was put in place. The tabbing kept the pad in place until the step was bolted to the compression post. I think that if I need to replace the core over the entire area over the post, I will have it done from the top and then be able to place the pad from the top.