I have noticed that when you level up more than once, it gives you the shards for your new level, and not for each individual level. (i.e. 1 → 4 gives you 40 + 40 + 40, one for every level gained. But it should be 20 + 30 + 40, if I am not mistaken.)
I do not remember this happening in my early days, so I wanted to report it, just in case.