Brian, I really wouldn’t take it too personally - the programmers at Davis always seem to be hard to contact - by anyone. Davis isn’t Microsoft - they only have fairly limited programming resource and AIUI they’re under a lot of pressure at present with several projects and deadlines all fighting for attention (just like any other smaller business really). Work is tough for everyone nowadays and maybe time spent on goodwill, but which doesn’t help towards meeting corporate objectives, is being squeezed more now.
And USBX is only one approach to mitigating the USB dropout issue. As has often been said previously and as you’ve highlighted again, attention to eliminating or suppressing RFI whether mains-borne or through-space seemingly remains the most effective answer.