I also did already wrote to support and pointing them to my post/this thread…
We will see, who gets an answer first…
About your idea about the “plate” - are you sure? Do you mean the black part of my close-up picture of the “outer contact”?
If yes: I think this is not the reason. Because if you look at my pictures of the jackstick without the FP-case: there is still some mm space at the outside, if the jackstick is connected properly.
IF it is about physical design: it would be more at the “end” of the hole" (=inside), as the jackstick stops there maybe to early (although there is a more deep hole inside, but which is smaller than the stick).
AND: normal earphone do work properly. So also the most inner connector is well placed and connected I would say.
I think the problem is more about a wrong (or different to FP1) connection of the individual contacts inside the jack or wrong recognition of the software or the dedicated audio-hardware…And I fear there will be no fix…What would be a high disappointment :-/
We will see.