My first thoughts were that it was an FSUIPC issue, so I've been working with John Dowson to try to identify the problem, he's been extremely helpful.
We can see what is triggering the problem, but are struggling to understand how it's actually happening and why it's only recently appeared.
The good news is that John has made a change to FSUIPC7 that seems to fix the problem for me with MSFS - I've asked him to do the same for FSUIPC6.
The version for MSFS (FSUIPC7) is available here
https://fsuipc.simflight.com/beta/Insta ... 18beta.zip
I'll let you know when the P3D version (FSUIPC6) becomes available.
Cheers,
Martin