I had to rewatch it a few times to see what you mean here....
He offers to replace ONE cap on the woofer circuit, that he "does not trust", a small electrolytic, with a new poly cap, if the owner of this version sends in the crossover board, AND GR Research determines it needs a new cap.
I have to wonder, if maybe they used the wrong value cap on some boards, or wires were accidentally wrong polarity and they are trying to a bit under the radar, simply fix a mistake they are now being made aware of??
After all these years, AND with the Advent of ASR/DIY Audio finding flaws, Danny is suddenly jumping into gear about this issue.....like a retroactive fix....Not saying it is a "Bad move" per se, but it looks like he is hesitant to admit to anything ever being wrong, or making a mistake.