Limpy
If the gun is right, it shouldn't hang up no matter how it's gripped...Two fingers...Upside down...Sideways...and all in between. However, some people seem to have a knack for inducing malfunctions in dead reliable pistols.
Don't overspring the slide. The heavier the recoil spring, the more energy required to send the slide to full travel.
Grip the gun as high as is comfortable or possible. A low grip causes the gun to pivot more readily, redirecting linear momentum into circular motion.
Use ammunition with a bullet that is neither too light (in grains) nor so fast that it gets the bullet free of the muzzle before full momentum has been imparted to the slide. In .45 ACP, 185-grain/1150fps loadings seem to consistently give more trouble than heavier, slower loadings. A contributor is often that the owner mistakenly installs a heavy recoil spring for such ammunition...which is backward. The recoil spring has not one thing to do with containing pressures in a recoil-operated pistol. Best to stick to standard or close to standard loadings...at least if you're after reliability.
Yours may not be grip-related at all. If the extractor hook is a bit too deep, it can get the rim into a bind with the ejector and hang it up. More often noticed with extended ejectors. Rim diameters vary within the same lot, which may explain why yours only does it on occasion. If you hook is right on the peg, a rim that is as little as .003 inch larger than the rest can induce it. One test is to measure the rims in a couple boxes of ammo. Separate those that are over .475 inch in diameter and see if they cause the failure to eject more often than the others. If they do, check your hook depth. About .033-.035 inch seems to work best across the board. No deeper than .036 and no shallower than .032 please. Adjust by drawing the tip sideways across a stone, checking often... and lightly radius the bottom corner. Barely breaking the top corner may also help.
Luck!