Cast on Block from Svalinn looks broken...

The Image shows it will give 250 Energy per Block and get 10 Maximum Energy per 0.1 Seconds of Base Cast Time of Socketed Spells.

In my Tests i put a spark into it so it has 70 maximum Energy.
So if I understand correctly, every time I block, a Spark should come out of me because I get 250 Energy per block and only need 70 Energy.

Unfortunately, that’s not happening! The gauge fills extremely slowly, so it feels like I need 50–100 blocks just to cast once!
So either it’s bugged or the description is wrong!

Overall, here’s some feedback if this is intended: It’s too weak… I’d have to let myself get beaten up forever just to cast once. That makes the item basically useless!
Suggestion: Significantly increase the Energy generation again, but reduce the damage of the socketed skills! For example, “On Block, you get 250 Energy, but triggered skills from Cast on Block deal 50% less damage!”

We could work with something like that way better than having to wait forever for a single cast.