Incorrect Phasing icon duration with Quartz Infusion

I am running Quartz Infusion on the Raider Ascendency tree which gives me Phasing during Onslaught.


Also whenever I kill a mob I gain Onslaught for 14 seconds, which also gives me Phasing for the same duration. However the Phasing buff Indicator incorrectly shows 4 seconds as a maximum.


After the 4 seconds, the Phasing buff icon disappears, but the phasing is still in effect allowing me to move through mobs.