They have found the 73 Classic doesn't like the combination of the undulating terrain in the undershoot of 17 and then the initial slope of the runway resulting in the aircraft landing half way down the runway
Jet2 have 737s of a similiar vintage and they never have to divert to Shannon, and they're subject to the same regulatory rules as Baby. Centralwings which operated to Cork until recently also have 737s of the same vintage and again they never had to divert to Shannon. I find it so strange that Baby have to divert on occasions when planes from all other airlines can land fine, including Aer Arann with their much smaller ATR72s.