I have exactly the same problem,but only if i put hyperpin in automatic startup when windows start.
When windows load,hyperpin automatically start.
Then i launch a table and ok,no problems.
When i exit,i return on the hyperpin menu but i always see dmd running in the second monitor and if i see in task manager i found ultravpserver and visual pinball there.
Seems like fplaunch cannot close this.....
Only 1 vpinball and ultravpserver process are present.
If i kill al the process and restart hyperpin then all is fine and i have no more this problem.
I also tried to put kill commands into the ahk,but i didn't manage the exact point where fplaunch manage to correctly close vpinball....and i tried many different points....
This problem only occur when hyperpin is in autostart with windows.
I've to turn on 1.295beta4 to correcty have this working.
Maybe you're able to manage this.
Please let me know.