By they way, it seems like we pretty much ruled out everything (SPAD, FSUIPC, signal degradation, many different plane developers, hardware bindings and valid in-sim situations)...
I'm slowly getting desperate. During flight I can just substitute NAV with HDG and it's not a biggie, but it repeatedly disconnected nav/gs on ILS approaches, which almost run me into mountains As such... did any one of the impacted people try reinstalling the sim or at least "repairing files"? I prefer to ask before trying it myself because I pretty much have the same install since MSFS2024 appeared and I'm not sure anymore if I didn't tinker with it in some way.