If you are in combat, and have a mob chasing you, there are certain areas, like fenceposts, logs, trees, inside tents, and others, that will cause the mob hp to reset, and any attacks will result in an Evade. After about 15-25 seconds, the mob will reset, running back to it's original location.
Here is an example (Un'Goro Crater) I jumped onto this log and the mob stopped following. I knew from experience that this was the evade bug...
Also, on a side note, many mobs that are evading may be killed, providing the following conditions are met:
a-The mob needs to be within melee range
b-The mob must have you targetted
c-The mob must be able to hit you
If these conditions are not met, it may still be possible to kill the mob within one to two hits IF the mob is not targetting anyone.