jeff does not need 6 bubbles

[FarmerInArmor]

jeff is getting away with stupid flanking nonsense because of his ridiculous 6 bubble count. Really a stupid part of the game that needs fixing

[Kuzenbo]

real

[Arcius Tiger]

The bubbles do have a significant cooldown time, so if a Jeff is escaping a lot with them then they're earning it through good resource management.
A good Jeff will carefully manage their bubbles since they not only heal, but increase healing received and give a speed boost. It's no doubt a powerful ability, but it has limits and certain heroes are really good at denying Jeff regardless.

Ask for someone to play Peni Parker to place mines in places the flank Jeff goes, all it takes is 3 mines to 1-shot a Jeff (just make sure they're placed together so they explode at the same time or else you're unlikely to secure the kill). Not to mention her net can CC the shark when they pop up to spit a bubble - takes fast reaction and aim though. Her mines are invisible and indestructible inside of her webs, so web the mines if they're being destroyed.

The important thing about flank Jeff is that it's best at distraction / mind games - it's aggressive and can be punished with good positioning, marking, and area-denial. Peni nest, Namor squids, anything to put consistent pressure on the shark so they can't stay around for long or have to deal with something before they start spitting at you.

Tip: Don't chase the shark unless you have a high chance of securing the kill. Distraction is a huge part of flank Jeff's value, focus on the team fight but keep the Jeff in mind.

[X Mal]

Its not the bubbles its his Hide and Seek ability gaining health when he is in it that needs to be fixed.

[Musoko]

Crazy how Jeff went from super strong at launch, to people thinking hes mid/♥♥♥♥, and now i've seen a ton of people saying hes OP again.

Shark Tuah will never die it seems