In numerous pictures I've seen while doing research, plus used RVs I've inspected, it appears that one of the longer-term problems is that water leaks under the floor of the slide (where owner can't get to it to dry) and sometimes soaks into subfloor, which can then stay wet for very long time because air can't get under flooring material.
I'd be concerned any visible water could be a sign of a larger hidden problem.
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