I had a point last year where most exes I made were being deleted instantly(strangely enough not all) In the end I sent my exe to microsoft and they verified it as safe and I had no issues since then
That's a good idea, I've sent MS b3d zips before to get checked but have never heard back from them, might try it again.
If it does work, it means having to do it every release I guess, but that's OK except there'd be a 'window' of false positives, unless you sent it long enough before release.