Long ago, I too, discovered that applying pressure to the protruding bottom of a Glock magazine meant for its bigger brother (e.g. G22 mags in a G27 or a G23, or G22 mags in a G23) could induce such malfunctions. You may notice that the extension on the slightly extended Glock-branded +1/+2 mags does not line up with pistol's frontstrap, unlike the aftermarket versions. I routinely avoid using the magazines intended for longer-gripped versions, or at least avoid applying pressure to the protruding end of longer magazines.
Although I haven't had the inclination to make an exhaustive study of this, I have also been able to induce such malfunctions with my other pistols (e.g. Berettas, SIGs and, yes, even my Colt 1911) It's obvious the more a magazine protrudes, the easier it is to change the feed angle and induce malfunctions, and Glock was among the first (if not THE first) to offer such a wide range of grip (and magazine) lengths.