Possible Bug Combining Armour and Energy Shield Mastery & Glancing Blows

TLDR: Glancing blows does not appear to be triggering the "Gain 5% of your Maximum Energy Shield" node on blocked hits that deal physical damage.

---

Testing Methodology: Tests conducted in The Control Blocks (Act 5), on a level 49 scion (Anastasian), in Hardcore SSF Ruthless Phrecia. The character had 40% chance to block attacks without Glancing Blows, and 78% chance to block attacks with Glancing Blows.

Control: Slave Drivers deal pure lightning damage with their Lightning Whip, and do not trigger energy shield regeneration with or without Glancing Blows.

Test 1: Slave Catchers appear to deal some physical damage with their ranged attacks. Without Glancing Blows specced, this damage consistently triggered the 5% energy shield recovery. Standing in a hail of ranged attacks did not result in meaningful damage. With Glancing Blows, this damage did NOT reliably trigger the 5% energy shield recovery, and the character could not stand in a hail of ranged fire without risking death.

Test 2: Without Glancing Blows, a hit from a single Slave Catcher always triggered the 5% recovery, and no meaningful damage was dealt to the character. When Glancing Blows was allocated however, ~4/5 of the hits failed to trigger regeneration, and the character would slowly lose energy shield. Given that my block chance was 78%, it seems likely that the regeneration is not applying to blocked hits.

Test 3: Removing "The Anvil, Amber Amulet" to decrease the block chance appeared to increase the percent of hits that were triggering the ES regeneration. I'm unsure of the exact percentage, but probably ~2/3 of the hits failed to trigger regeneration with the amulet off?

---

Conclusion: This interaction seems like it isn't working quite right. The tooltip text for the mastery states that you "Recover 5% of Energy Shield over 1 second when you take Physical Damage from an Enemy Hit", and glancing Blows causes you to take 65% of the incoming damage when you block a hit. As written, it seems like the regeneration should be applied whenever you block a hit that contains a physical damage.

Is there something here I'm missing?