I had never heard of the 30 second issue until this thread.
A few years ago I had something like this on Merion, number 3 I think, the long par three where the ball hit above the hole, stayed there for a while and then slowly trickled down toward the pin yet stopped a couple of feet above it while still rolling pretty good. I don't know if it would have gone in or not but strange that it stopped there, guess I know why now.
I guess it can help or hurt you so it isn't the biggest deal in the world.