waitproperty waits the entire timeout value even after the property value is true

I use WaitProperty and WaitWindow regularly in scripts and haven't seen that problem.  Is there a chance it's not finding the button for some reason?  Maybe the identification properties on your button? 

Also, if you comment out your line with the WaitProperty does it find the button when you attempt to click on it?  If should wait for whatever amount of time you have set for the autowait in that case.

For debugging the problem I'd be tempted to use the "If statement" approach shown in this topic:  Checking Whether an Object Exists | TestComplete Documentation (smartbear.com)

Using that method you could at least verify whether or not the WaitProperty is really finding the button at all.

Best regards,

John