[Gameplay] Twitch with Ult targetting Nexus...doing no damage.

While in a recent very close game where I was playing Twitch, I had snuck to the enemy nexus (no turrets) to finish the game. I clicked my ult beforehand and right clicked on the nexus. Twitch began to shoot his arrows at the nexus, yet was doing no damage. In my confusion, I looked to see if the inhibitor was up, and it wasnt. I suddenly realized too late that apparently, for some reason, he might be too far...even though he was auto-attacking it normally, which made no sense. Having lost those few seconds of my ult and not attacking the nexus, I was overwhelmed.

Why is Twitch auto-attacking a target at full range with his ult...but doing no damage? That has never happened with me before. This seems like a bug in the coding of the boost the Ult gives compared to range.

No where in Twitch's ult does it mention this concept of 'missing' a stationary target. Here is some info:

_Active: Twitch gains bonus attack damage and his basic attacks have 850 range for 5 seconds.

Bonus AD: 20 / 30 / 40

Additionally, Twitch's basic attacks travel across their full range and skewer every enemy they pass through for the duration, dealing 100% - 40% (based on enemy hit) damage. These attacks apply on-hit effects to all affected enemies and can critically strike against each individual target.

Spray and Pray is a self-targeted buff with a linear area of effect component.

Does not apply spell effects.
The enhanced attacks fully apply life steal on all targets hit.
Spray and Pray can be  dodged,  parried,  blocked, and be negated if Twitch is blinded.
Spell shields will not block the ability.
This ability is considered to be a projectile Unbreakable and Wind Wall. 

Additional Information:

Spray and Pray has no cast time and does not interrupt Twitch's previous orders.
Spray and Pray enables Twitch to outrange turrets by 50 units, allowing him to hit them without them returning fire.
Twitch's enhanced attacks will pass through terrain and enemy structures (the latter will not be damaged unless being directly targeted while Spray and Pray is active)
Runaan's Hurricane's Wind's Fury interacts with Spray and Pray's bonus attack range but not with the enhanced attacks (the secondary bolts will not pass through enemy units, enemy structures, or terrain)

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