That change is significant. Two 15 min periods are hardly enough to saturate raised beds to the point of running off. I'd suggest your timer may have gone faulty.
That amount of water shouldn't have left the beds.
We have a large soakaway we constructed 12 years ago following the instructions of the pavingexpert, it's collecting and dispersing all the land drainage water we installed on a half acre garden (high rainfall here). It's still working perfectly, no soggy areas.