Glitched monsters?

I've noticed every so often, a monster takes a lot less damage than normal and doesn't give exp or weapon prof, and I was wondering if anyone knows what causes this?

I've been told by some people that this is caused by the packets that botters send, but I didn't know what to believe, so I thought I'd ask here, because if anyone would know, you guys would =)

+thanks to any useful answers.

For what I know is just a bug that has yet to be fixed by TQ =/ and I hope they do it soon cuz it screw xp skill.

Thx for that, still waiting to see what other answers I get though.

yeah, im pretty sure that its just a bug that TQ needs to fix, but if u go on any server straight afterserver maintenacnce, there wont b a single 1 for quite a few hours so u can b sure that ur good =)