One just needs to wonder how & what sort of parameters were used to estimate the first superblock difficulty before it took off. Had I realized the shortfall of the superblocks timing I'd have warned Gatra but correction is still aplenty. It's just a matter of choice, etc.
The timing is based on block intervals, rather than a set time of day, so the exact time is not set, and will depend on mining power, difficulty adjustement and a bit of random, so day and time will drift over the course of months/years.
First super-block was at 19:50, latest was at 22:07, and we had one at 22:30, so it's not a huge drift, but it's a drift.
So chances are the dry spell will last a few weeks, until we drift to the next peak.