This was reported in another thread, and I'm seeing it to when I test (on 2.2.8.141, though I'm not sure if it started sometime or hasn't been there since the first 2.2.8). Here's the other thread:
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 ).