We don't have any give in our floor, you ought to take a closer look. Order one of these Moisture Detection Meters from Amazon and check your floor from time to time, especially around the perimeter. Make it part of your routine inspection and maintenance. It has two probes on wire leads that you can reach into corners, probe right through the vinyl finish floor into the plywood subfloor and you will know if there is moisture, which will most probably be present of the floor is rotting. Sharpen the probes with a small file to make it easy to probe through, the mark in the vinyl will disappear if you don't push into it too far.
Doug and Cheryl
2012 FC RB, Michelin 16, ProPride 1400
2016 Ram 1500 Laramie Crew Cab 4X4 Ecodiesel 3.92 axles
The Truth is More Important Than the Facts