Built to last doesn't work on skeleton keys?

DarkJokerOfAmuro

So I was in a match against a deathslinger while playing as a Jane with a skeleton key and I have the add-ons milky glass and blood Amber. On my perks I had StreetWise as well as green built to last I made sure to monitor my use of the blood number very casually and I had only ever drained it once fully however I noticed that built to last didn't even activate, and my key was forever depleted throughout the rest of the match. Was this part of the supposed key Nerf because because it doesn't make sense considering the perk is supposed to restore any depleted item regardless of what it is except for flares and flash bangs and fireworks.