just noticed this earlier
and just searched the forum
didn’t know this was a known bug
when Coursing/Retrieve kills a mob before the duration ends, they will stay at that position, issuing a command is futile, since they wont act it out, it looks like the sprite will, but they will rubberband back until the skill duration is over
is this fixed in kToS?
hope it gets fixed, having charges on those skill is useless if you cant use them anyway 
to avoid this problem i use rush dog (short CD good damage) so its behavior is reseted or just use point
For Retrieve, you can walk to your pet and it will be ready to go.
Pretty much as Liledern said. Retrieve has a condition for it to break the skill, which is if the pet is able to reach you during the skill duration. Coursing does not has such a condition,seems like somewhere somebody forgot to add a line saying to stop coursing if the enemy dies. The trick to avoid the pet being stuck is to use retrieve before the mob is dead (or for chaining a super long CC on somebody). That way, you just have to wait for the pet to come to you or just walk to him and everything is fine.