[Gameplay] Mordekaiser's W loses 2/5 of its duration when attaching to an ally unit

THE BUG: Mordekaiser's harvesters of sorrow (W) is supposed to last 4 seconds. When self-cast with no nearby ally units, it gains its full duration but deals no damage to nearby enemies.

BUT! When it attaches to an ally unit, it INSTANTLY loses approximately 1.4 seconds off of its duration (judging by the duration indicator on the buff bar) essentially shaving a massive amount of damage and movement speed off of Mordekaiser.

Steps to reproduce: Use Harvesters of sorrow on an ally unit. Watch the duration immediately decrease from the full duration to almost halfway through as it attaches and the damaging circle appears.

100% accuracy - this occurs every single time the spell is used and it latches onto a nearby ally.

This shaves off a lot of trading power for him as this is his main damage source and trading tool.

I can record the bug and upload the clip here if its necessary