Some mobs performing movement attacks keep doing them even when netted.
Animation shows them doing their attacks dragging the net …
Bug?
Possibly. LE considers skills that move the character separate to “normal” movement (walking), this is why you can use movement skills to get through walls that you would otherwise have to walk around. The “using a skill” state is different and separate to the movement state a character is in when they are walking.
But if you think it’s a bug, report it.
I understand the 2 different “modes” but, from my perspective, that would void the purpose of the net.
Maybe the devs should consider if that was intended or if it could be twicked to make netting more appealing and adherent to reality.
I mean, if intended then make them break the net and be free i/o moving around netted 
Absolutely & that’s why it’s a bug. You’d expect the mobs to be immobilised with the possible exception of if they had a skill that enabled them to cleanse negative ailments (which they don’t).