While this is not "common" (we build a LOT of boats) we have had a larger experience of drive well cracking than is acceptable for sure. A search of topics will tell you that Outbacks and Adventures models (Primarily) experienced some production issues back in the early 2000s.
Here is a tech bulletin released in the forums back in 2009 on the subject: http://www.hobiecat.com/forums/viewtopic.php?f=21&t=12571
81410011 MirageDrive Well Retrofit (For Outbacks and Adventures only). Outbacks [older] than July of 2003 would not use the bolts part of the kit.
Extended Warranty Coverage
Our normal two-year warranty coverage for Outback and Adventure hulls will be extended to four years with 100% coverage for damage to the well on kayaks in the specified range. After four years there will be pro-rated coverage on those hulls for an additional two years.
Outbacks with serial numbers A3753 through F2853
Adventure with serial numbers D0001 through D1875
Molded fiberglass fitting
Loctite Epoxy Pack
(2) new knobs (in case of some damage)
(2) longer bolts (tapered ends)
5/16" allen wrench
Here is the instruction:
Hobie Mirage Outback and Adventure drive well strengthening kit.
Note: This complete kit may not be needed for older Outback models due to the length of the camlock knob bolts. Outbacks built before August of 2003 (Serial number 3753) should not need the longer bolts. Those boats would have appropriate bolt lengths. Boats built after that serial number are suspect due to a change in the mold shape.
It has come to our attention that the camlock knobs can flex out of column under heavy loads. This may allow the knobs to ratchet.
Director of Parts and Accessory Sales
Hobie Cat USA