The UAC plug-in is difficult to use correctly so please consider a different approach.
Your code is fundamentally broken, you cannot combine RequestExecutionLevel admin and the UAC plug-in!
You are not quoting the path in ExecWait and it probably should be silent.
Normally I'd ask you to report your Windows, NSIS and UAC plug-in versions but your insufficient and broken example code is not worth my time trying to reproduce your problem...
IntOp $PostCount $PostCount + 1
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