When my membrain was destroyed it looked like yours you can try to clean it with some IPA, AC said put a few drops on and then just absorb the liquid with some paper towel, don't touch it more than just resting the paper on to absorb. Repeat 5 times.

For me this also didn't work so they posted me a new membrain and it went back to it orginal behaviour, which for me is also not working as expected but I never found solution so far either. I suspect as someone pointed out in a previous post that its a bad rotary fitting but I didn't get time to change this yet, like you I rebuilt the hole loop checking all the fittings 1st but to no avail.

I am able to run in monitor mode so you could try this after fixing the membrain issues.

It seems that the membrain issue in my case was using EK EPDM tubes but you seem to have hardline so I'm not sure in your case, anyhow they said for the EPDM that there is something that leachs out of the tubes that trashes the membrain so after this is leached out then it should more roubst so it should be an unfortunate inital membrain loss but more robust afterwards.

it looks like your Membrane is defect.
Install the latest insider version, test the Membrane/Device with the System->Test.