Grebe : and/or improperly checked tooling size ( coldwork mandrel ) is the most likely issue. ( see Fatigue technology )
If the cracks are originating at the fastener holes I do agree with your statement.
Cold Working of holes is very important to relieve stresses as well as proper fastener hole size and proper installation of Hi-Loks.
Hi-Loks are usually installed interference or close tolerance fit.
https://www.aerofastener.com/products/hi-lok-pins
Shot Peening and Flap Peening are also important post assembly maintenance processes on various structural members and parts that also relieves stresses.
Note: I posted this info for folks who have never cold worked holes or installed Hi-Loks.