Might be by design, but I would hope not. Bulwark Core is NOT beneficial to the player. There is absolutely no way to recover the shield. I assumed that maybe med stations would restore it or that it would be restored during a jump, but no, it stays gone FOREVER. This is not beneficial. In the average ground event the player will lose that entire shield even if they are relatively careful. And it costs 3 points at that. The idea that you can't recover shield IN A FIGHT is a cool concept, but as it is, this is an actively detrimental perk that just disables your shield for most of the run.
I suggest reworking it in a rather simple way: Why does this need to be a shield perk? You've made the shield function like health, so why not just make this perk just set shields to 0 and grant a large health boost? This would allow recovering from healing sources, and still disables shield recovery.
New text: "+300 health, but personal shield is disabled." I feel this would be a in or around a 5 point perk. I'd consider running this, and it has potential to combine in fun ways with some artifacts like friendly fire or forced recycling.
Either way, in it's current form, I cannot justify Bulwark Core in any way, other than it being an actively harmful perk that wastes points, disables your shields, and exclusively hurts the player.