That plywood WAS a baffle..........it was there to direct air out upper vent.
It was attached somewhere and has fallen down/out of place.
As shown here it would be the 'sheet metal deflector' and installed at an angle.

Could have been installed by rv mfg./fridge installer
OR
DIY project by previous owner (or at an rv shop) due to previous cooling issues.......lack of proper air flow/draft.
Fans cycling.......
thermodisc on condenser fins should turn them on when fin temp is 130*F and off at 115*F. (15*F difference)
So fans are working and temps change.....but only 10 seconds for temps to increase could be because of that baffle fallen down/dislodged and now missing.