Autohotkey run right only at odd times pushing button on Reaper the music production software. Run completely right on notepad

Question

I have an Autohotkey script that is a bunch of code in this form for example:

m::
    clean:="{BackSpace}S{Space}Clean{Enter}"
    If (last_effect <> clean)
    {
        Send, c
        Send, %clean%
        sleep, 01
        Send, {Esc}
        last_effect = %clean%
    }
    Else
    {
        Send, ^!{Down}
        sleep, 01
    }
return

The code above will execute when the m button is pushed. If last_effect is not "clean" (in string), it will turn on a typing box in Reaper the software by sending c then type "clean" in it, delete unnecessary words, then enter. Else, Autohotkey will send Ctrl Alt Down to move to the next track in Reaper.

The problem is the Autohotkey only does it right when I pushed m 1, 3, 5 etc. odd times. When I pushed m 2, 4, 6 etc. even times, Autohotkey did it wrong, appeared a little error box and disappeared too fast I could not see what was the error. Then it sent the wrong keys. I tested the script on notepad (open notepad and push the button for Autohotkey to send keys into notepad), it did right in both odd and even. Maybe the problem is in Reaper I have no idea.