More an unintended aftereffect really. This is down to the specific monster AI.
When a player casts LR and monsters around them are affected, it should look something like this:
x - monster
o - player
x x x
x o x
x x x
Upon being affected by LR, the monsters will walk in the opposite direction away from the target. If the monster's pathway is blocked (like the one you see in the top right corner of your video), it will attempt to move around the obstruction, rather than choosing a different pathway that isn't obstructed.
Your ranged monster types will continue attacking the target even under the effect of LR but will still try to move away from the target, you may have noticed this same effect with Right/Left Guards in the past - they run away but continue hitting you with fireballs/lightning. The same thing happens with archers.
As for the SvaltusFighter on your bottom left that just stands there, that looks more like an error with the AI itself and that specific position away from the target.
- - - -
- - o -
x - - -
Looks like a case we need to potentially look at making changes to the pathway-ing for monsters affected by fear effects.