So, when I kill a monster I gain no exp, the same goes for when I loot meso.
On the bottom right, above the UI after the monster has been killed there's no EXP gained message.
As for my exp bar, it goes unchanged as well.
And as you can see here, the meso message doesn't appear like the EXP message.
This doesn't happen on my other characters though, just this one.
Edit: Strangely after staying logged off for a while and coming back, my EXP/Meso gain seemed to have fixed. I'm confused now.