In the meantime, if you're using "This Rule" and are only trying to cancel a delay, there is an easy workaround (I often see people sort of over-using it for this purpose, but you might be more familiar with RM than that ).
I needed Cancel Rule Timers to stop a fade. As a work around until it gets fixed, I created a second rule that has no trigger and does nothing but Cancel Rule Timers in the first rule. Then I run that "cancel" rule in the first rule. Hokey but it works. When the cancel rule timers is fixed, I'll only need to replace that one line in the first rule.