Shadowtrap isn’t actually a teleport; it is a shadowstep like the rest of the ‘teleport’ abilities for thief IE infiltrator’s strike and signet ect. What this means is that rather than cleanly teleporting to the proposed location, you instead ‘shadow walk’ there, which is a tie into the old guild wars 1 shadow realm. Since you are effectively walking the full distance instantaneously, you can run into some issues with terrain if there are any breaks in continuity, as in all of the ground covered isn’t considered part of the same ground. Almost alwyas when an error with this happens, you will not go anywhere at all when you finish casting the trap. Similar things happen on other skills, but most, like Infiltrator’s arrow, will give you a ‘No pathing" error message and not go off. However, in the case of shadow trap, this doesn’t happen, and instead, the skill is wasted. The other case when shadowsteps snag is when the target location is too far away from the cast location, in which you will go the maximum available range toward the target location. Where this gets screwy is when you look how the game considers walking distance for this, going off a displacement. Just how the shadowstep system works, and until it is overhauled, which i can’t see happening, or until shadow trap becomes an actual teleport or ‘blink’(See mesmer), this will just remain something you have to get used to. On a side note, there are so pretty nifty features in this type of setup, though with minimal usage.
TLDR: Shadow trap is a shadowstep, not a teleport, which makes it problematic. To avoid tripping it up, make sure you have a clear walking path to the intended location, and that the ground you are teleporting across is a solid piece. By now most things will be combined to be a single piece, but there are areas that aren’t ideal.
