Yes.
Typing a keystroke that is the hot key trigger for an active macro has unpredictable behaviour, it may type the keystroke or trigger the macro, and which will vary depending on unpredictable factors including the load on the Mac, the version of OS X or Keyboard Maestro and other factors.
Your style of macro is a typical example and the failure mode you'll see is that sometimes the macro will take longer to function than normal, because the macro is actually being triggered a bunch of times before the keystroke is typed instead of triggering the hot key.