Something to Check
There have been a couple of cases mentioned in VAF where people have reported encountering the very onset of flutter. One pilot described it as a "buzz." It's not common among RVs.
Before retiring, I was an aerospace stress analyst. Not long ago I got to examine some wing parts, not from an RV, which had fluttered.
What I learned from that is that if you think there might have been flutter, to check (among other things) the rod-end bearings. The ones I looked at had stretched slightly. Just something that might otherwise go unnoticed and lead to looseness, which in turn could lead to flutter at a lower speed next time.