I've been noticing this on-and-off, but it was particularly problematic in the first area of the Lost City of the Na-Totambu. Sometimes Trample will stop literally just in front of my character, other times not fire at all, and even a few times I get an Invalid Location error on the top right of the screen.
Echoes from the west, great hammers will fall...
Under high rocks all will answer the call...
Bring us your arms, pariahs of yore...