When you "tap the next downbeat" the ACW begins to recalculate the barlines, trying to keep ahead of the song playing.
Did you continue to hit the F8 key to set a few bars so the ACW had something to work with?
Hitting it once told it you wanted to change what it had done, and it may have been waiting for a second (or third) tap so it had something to calculate with. Especially after making time signature change to account for timing.

Also, 2008 version is a little dated for us users to check with, maybe an update will have a fix involved, or it is possible that an older system doesn't have the resources to allow the ACW to calculate ahead in realtime ..
what are the computer specs?


I do not work here, but the benefits are still awesome
Make your sound your own!