Gas Grenade: Fuse Duration not reduced by Skill Duration modifiers

For Gas Grenade, the Fuse Duration is not affected by Fast Forward support, or any of the "Reduced Skill Effect Duration" nodes (next to Near at Hand notable), or even the Volatile Grenades notable.

I timed it with a stopwatch, and it seems like it's permanently stuck at 1.5s even though the tooltip claims 2.0s without any passives and goes down with the passives.

Long Fuse support does make the time longer, and when using it the tooltip number (taking into account the Reduced Skill Effect Duration) is correct.

Doesn't seem to be the case with other grenade skills.

Did a few more tests, and it seems that the Fuse Duration is in fact affected by everything even on Gas Grenade, but there is an interaction (only for Gas Grenade, no other grenades) where if you fire your grenades close, it makes the fuse time shorter down to something like 1.4s. The flip side is that Fuse Duration for Gas Grenade cannot go below this number, even if you spec into Skill Duration.

This interaction does not happen when Long Fuse is used, but otherwise this means that the Cluster Bombs passive is basically free when using Gas Grenade and Fast Forward support is completely unnecessary.

Is this intended?

Here's a short video showing the bug: https://www.youtube.com/watch?v=mWqqJlgZHh8

In the first clip, you can see Gas Grenade exploding faster on the left (shot shorter); in the second clip, you can see how Explosive Grenade does not have this behaviour. In the last clip, you can see how Gas Grenade with a 3s fuse duration explodes faster than a Explosive Grenade with 2.62s fuse duration.

i noticed this too, started building voltaxic which says 1.2 second fuse time but was taking like 4 seconds

Is there a unique that can provide reduced skill effect duration?