DetectHiddenWindows, On IfWinExist, ahk_exe obs64.exe WinActivate, ahk_exe obs64.exe

IfWinExist, ahk_exe obs64.exe Send, {Alt down}{Shift down}r{Alt up}{Shift up} ;alt+shift+r is my stop recording hotkey defined in OBS

Sleep, 5000 IfWinExist, ahk_exe obs64.exe Send, {Ctrl down}{Shift down}r{Ctrl up}{Shift up} ; ctrl+shift+r is my start recording hotkey defined in OBS

Sleep, 2000

ExitApp

There must be some incompatibility with a simple hotkey like 'r' that prevents OBS from seeing it. I would also test this repeatedly within a session of OBS and I think changing the hotkeys don't work with AHK until you exit and restart OBS (even though using the hotkey within OBS works when using a keyboard, simulating keystrokes with AHK seem to miss without a restart). If someone discovers the real reason behind this, please post it. thanks.