No, Shields are working fine as far as I can tell, its just the "Feed back" that is Bugged.
If you give it regen, and let it sit for a while, the shields should regenerate, and you wont be able to break blocks. But the shield doesn't change colour when they get critical, nor does the Status (the Number shown when you select them) change from 100%.
Basicakky they work fine, but they just dont tell the person shooting them when the shields are empty. (As far as I know)