Cap sam wilson bug?

Poup

If i understood well, i should be able to block any unblockable attack as long as i have a bullwrak buff active, right? Doesnt seem to working so well in many fights/nodes..
Did i misunderstood something or is that a bug?

magnus_xix

He can only block unblockable special attacks from mutants and you need an armour up to do so not bulwark