I do not know how the warpage happened after 2 years of use. Usually if a cue is going to be warped, it should happen within a few months especially it is used often. Has your cue ever experienced a severe climate change, or taken on a flight? Sometimes a simple reface at the joint can make the cue look and play straight.
I just recently met a guy who's had a coker for over 7 years (old style bumper with the screw into the bumper for you coker fans that know when he used that style bumper) and it was straight the entire time he had it. just last month the thing warped on him. woods funny sometimes