Max rage passives not carrying across weapon sets

This may be a bug specific to "while shapeshifting" passives.

Scenario
Playing with Talisman and Staff, I allocated the "Primal Rage" cluster that grants total "+18 to maximum rage while shapeshifted" on weapon set A (talisman). For weapon set B (staff), I allocated the "Anger Management" oracle cluster that grants total "+21 to maximum rage". So playing with talisman, I should have 48 rage while shapeshifted (which I shapeshift by default) and I should have 51 rage in human form with staff.

Problem
When weapon swapping from staff to talisman at max rage, I can see the rage bar cut down by ~33% (I cannot see the exact numbers). I expect swapping from staff to talisman, my max rage would go from 51 to 48, meaning my rage bar would be full. That is not the case since the bar lost a noticable chunk of rage. This may be due to the "while shapeshifted" condition on my talisman passives. It is like the max rage is removed (51 -> 30), then the shapeshifting condition is met to increase my max rage (30 -> 48) and leaving a chunk of missing rage because it capped it down to 30 first.

Going the other direction works as expected, talisman -> staff does not noticeably change my rage bar. I would be going from "+18 conditional rage" to +21 unconditional rage".

Reason to fix this
Playing with weapon swapping, only getting max rage while shapeshift means that when I cast spells with staff then change back to shapeshift, I lose a chunk of rage because the max rage is lowered with the staff weapon set passives. So I specifically allocated weapon set passive points to get max rage for staff, keeping max rage roughly the same for both weapon sets so that I would not lose it when swapping back and forth. I want to play mainly with shapeshift, then quickly throw down vine spells and swap back, but currently I lose a good chunk of rage and it is annoying to have to build it back up, making it hard to justify frequently weapon swapping.