Possible Xp Glitch?

Hey guys I'm new here so I don't know where to post this question so I'm just posting it here!

I'm currently level 15 and I had a good session of viciously grinding xp. After killing what seemed like at least 50 mobs I looked at my xp bar and it hadn't seemed to climb very far. I was somewhat frustrated and I wanted to get to the bottom of this.

I then created a theory, after testing it out on lots and lots of mobs I concluded that:
1. I didn't get any xp from kills with my spells
2. I only got xp if I beat them down with my daggers

I was just wondering if this is intended or if I'm experiencing some sort of bug. If it is the latter can someone tell me how to fix it?

 

1. It could be a bug
or
2. You could have been killing too high or too low level mobs for your level. Every level difference makes it so you get 3% (I think) more likely to get 0 xp instead of the normal amount. So if you were killing level 10 mobs you would have a 15% chance of them giving you 0 xp.

 

make sure youre grinding on level 15 or so mobs. if the mobs level is to low or to high you wont get xp. this prevents power leveling