I saw there are more people asking for this same issue, but there is no solution for it yet. Topics are closed without a solution.
On my new installed system with Win10 x64, PinballX 2.36, Pinball FX2 (non steam) I encounter the same problem.
Pinball FX2 tables are starting from the PinballX menu but when I exit the table it will return to PinballX but the backglass and DMD are stuck on the backglass monitor and Pinball FX2 is still playing in the background. I can't start a new table from this moment until I close Pinball FX2 myself.
I also tried a KillTask.bat and use it as a Launch After in the settings like someone mentioned, but this isn't working too.
Hopefully someone knows a solution or workaround.
PinballX.ini
log.txt
KillTask.bat