Almost every feature in mIRC uses ticks for time measurement. There were only a few featurs that did not and those are the ones that were changed in the beta. An example of a timer that was moved from using system time to ticks is the timer in the Timer dialog.

If you instead set the clock forward by 1 hour

There are no plans to cater for this or other side-effects due to changes to system time made by the user. Once we start down this road, we would end up having to take into account every conceivable side-effect, which is beyond what mIRC is designed for.

The current change was simply to move from system time to ticks for some features, to conform with how all other features measure time.