Charge duration does not work with Perfect Warlord

The Perfect warlord shares Endurance Charges with allies.

I bought a charm with a 45% charge duration, expecting the 10-second duration to go up to 14 seconds, but it remained at 10 seconds. I then specced into the 20% endurance charge duration node, and my endurance charges remained at 10 seconds.
So it does not seem to be an issue with the charm, but rather the spectre.

I was about to report this, have the exact same experience. Charge duration doesn't work on charges generated by perfect warlord.

Same

Having the same problem with The Restless Ward chestplate.

Same