We've managed to replicate the issue, it looks like the "Lead-in drum count if drums muted/disabled" checkbox in Count-in/Metronome Settings turns that click on or off (it goes away when the box is checked). We do have one machine here that never gets the click though, so there's likely another setting somewhere that also affects this.

I'm reporting it now, thanks for the heads-up!

Cheers
Kent
PG Music