The "weighting" of the signal being sent to the meter from Forward and Reverse is likely different, so as to provide the right SWR meter readings. Flipping it around is going "around" those distinct weightings - I would not conclude the meter is bad from this test.
This was very informative! Thanks for making this video! I have an SWR meter that I just bought used that I suspect is not functioning because I’ve connected it to 2 different CB radios and the meter never moves. The one CB is brand new. I think I’m gonna have to open up the meter itself and have a look inside. That’s really cool about reversing the dummy load and making it understandable about the change in operation of the switch.
I found the same result after accidentally connecting my SWR meter the wrong way round and the FWD/REF switch worked in reverse. That was in the early 80's.