Carry weight reduces when entering Power Armor

The only thing I can think of is that if you are wearing a lot of "Pocketed" armor pieces before you start using Power Armor, you would be giving up the extra carrying capacity that the Pocketed mod offers (30 total if you have both arms, both legs, and chest pieces "Pocketed"). But the increase in carrying capacity due to the Power Armor strength upgrade should outweigh that. Perhaps the strength boost from Power Armor doesn't affect encumbrance the same way it would if you were to add a SPECIAL point to strength?

Related: How much carry weight does "Pocketed" add?