Soft Floor???

[sourdough]

Just looking for thoughts before I go spend money.....

DW said she thought the floor at the end of the island was getting "spongy/soft" maybe 3 weeks ago. I walked across it and it seemed alright to me but she keeps saying she can feel it thinking maybe the flooring has raised off the floor joists or?? I've walked across it a few times and it seemed like it might have felt soft but I haven't really worried about it.

2 weeks ago I came down with what I assume is a "Plantar's heel"?? Due to that I bought a new pair of Brooks tennis shoes because they were recommended. I have worn boots all my life which feel pretty firm when walking but the tennis shoes aren't like that. I've now walked across the floor many times and it DOES feel like it may be a little soft/spongy. As I've tried to muddle through this a question came to mind that someone may have insight to:

We keep a 35 pint? dehumidifier running at the end of the island right in front of the spongy area. Floor is never wet; keep the unit drained etc., but, it does get warm when running and at times puts out warm air. It's out there I think BUT - reckon the dehumidifier running could be heating up the floor and causing condensation underneath which then softens the floor?? With the weather fluctuations we are having I think it could be possible but "through the floor"??

Throwing that out there for thoughts. At the moment I intend to take it in when we get back to TX and have them pull the coroplast to check for any problems that may be there....due to them replacing it twice and what appears to be a leak out of the bottom when the galley gray tank fills (thinking a screw got it).