Sanguine pool bug [Gameplay]

As an enthusiastic Vlad player, I have always loved the concept behind his W. While this spell functions properly in almost all cases, there is an issue that arises when it interacts with Thresh's ult and similar abilities such as Veigar's Event Horizon. Despite the spell description, Vladimir is not actually treated as "untargetable" when he passes through the walls of either ability. I would understand if these abilities simply bypassed the entire concept of untargetability, but with abilities like Fizz's Playful/Trickster, and Zed's Death mark being able to bypass the walls just fine, it seems like Vladimir is being unfairly punished. Below are ability descriptions and results of the interaction to further clarify the discrepancy between what the spell says it does, and what it actually does.

Death Mark Cost: No Cost Range: 625 Zed leaves a shadow behind and dashes to target Champion, marking them for death. After 3 seconds, the mark will trigger, dealing a percentage of the damage Zed has dealt while the mark was active. Zed briefly becomes untargetable and spawns a shadow at his location that lasts for 6 seconds.He then dashes to target champion and marks them for death. After 3 seconds, the mark will trigger, dealing physical damage equal to 100% Attack Damage plus 20/35/50% of all Magic and Physical Damage dealt to the target by Zed and his shadows while the mark was active.After 0.5 seconds Zed can reactivate Death Mark, causing Zed to switch positions with this shadow.

Result: Bypasses box walls and walls of Event Horizon

Playful / Trickster Cost: 90/100/110/120/130 Mana Range: 400 Fizz hops into the air, landing gracefully upon his spear and becoming untargetable. From this position, Fizz can either slam the ground or choose to jump again before smashing back down. Fizz hops toward your cursor onto his spear, becoming untargetable, and then slams the ground dealing 70/120/170/220/270 (+75% Ability Power) magic damage to nearby enemies and slowing them by 40/45/50/55/60% for 2 seconds.Reactivating this ability while Fizz is on top of his spear causes Fizz to jump again towards your cursor and deal 70/120/170/220/270 (+75% Ability Power) magic damage in a smaller area to enemies nearby, instead of slamming the ground.

Result: Bypasses box walls and walls of Event Horizon

Sanguine Pool Cost: 20% of current Health Range: 350 Vladimir sinks into a pool of blood, becoming untargetable for 2 seconds. Additionally, enemies on the pool are slowed and Vladimir siphons life from them. Vladimir sinks into a pool of blood for 2 seconds, becoming untargetable and slowing enemies above him by 40%.Vladimir deals 80/135/190/245/300 (+15% of bonus Health) magic damage over the duration and heals himself for 15% of that amount.

Result: Slowed and damaged by The Box walls, stunned by Event Horizon

As a Vlad enthusiast, I only ask that you look into this issue and either make vlad able to pass through these abilities, or normalize it so that they box all forms of "untargetability".

Thanks for your time, Total Templar