Traps created by such combos ordinarily move toward Link only when they also move toward the middle of the screen, and they then stop at the middle (just like traps from Zelda 1). However, when placed in the middle of a screen, the trap will dart after Link in either direction and continue through any solid combos right off the edge of the screen from whence it will only return if you leave and re-enter the screen.
Trap (4-way) combos exhibit the same behavior when compelled to move horizontally. All vertical movement of trap combos seems normal (in the direct center, they simply don't move which makes sense).
I'm not seeing this bug, so it must have something to do with a trap-related quest rule. Could you please post an example quest?
It just uses whatever the default quest rules are. Here's a simple example quest saved in b448.
http://files.filefront.com//;7995749;;/
This bug still persists in 539, though you must turn off the default quest rules governing trap movement now (back to how they were set in 429 when I first reported this). They behave correctly when the rules default in 539 are checked.
I posted a sample quest demonstrating the bug, but this report continued to have the ? symbol. I'm not sure what the deal is.
I'll change it back to the bug symbol so it will be looked at again for you. 😉