Well, that rules out managed flights - such as the discovery flights - as the cause for what you are seeing.
So, the next question is what has changed on your PC recently? Any addons added / upgraded / removed? Maybe one of them is now unintentionally causing this.
Also, some aircraft store data in the “…WpSystem\ a-long-GUID-name-here \AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalState\packages” folder
(The exact location of the folder depends on how you installed MSFS).
e.g., for the default A310-300, see the files in:
…WpSystem\ a-long-GUID-name-here- \AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalState\packages\microsoft-aircraft-a310-300\work\panelstates
I’m wondering (pure speculation here) if there is something in one of the files in that folder that has changed & is causing what you are seeing. As I don’t own the Black Square Baron 58P, there is no way for me to know.