This usually occurs when the minion is inside a “U” shaped area and I am asking it to move to the base of the U, but outside (i.e., where an underline would be on an underlined U.) My character is at the underline as well.
Rarely this also occurs when the minion is fighting off mobs around a gate. I can’t quite quantify the exact trigger, but it seems to occur when the gate is exactly between the minion and the newly-spawned mobs.
In both failure modes, the minion just stays where it is while you spam A to try to get it to move.
Putting the A location elsewhere so there’s a direct path to go to has “fixed” the problem in the past.
To make this bug very clear – yes, a SHORT path exists. The minion simply does not find it.