Wat glitch

There is no glitch, people are using this as long as JML exists. Some put him under Bastila lead to make it even more powerful.
Show us your SEE and the enemies JML you're fighting with.

Easiest workaround is to include (raid) Han Solo on your team and use Shoots First to Stun Wat and prevent him from ever putting the tech on in the first place (ideally include team members who can continue to stun/ability block/cooldown increase Wat while you focus him down).

Failing that (and without knowing your roster), Rey and JML, particularly if you include GAS/JKL/Hoda/JKR in the team, can both put enough focused damage on JML to outstrip the protection recovery.

No glitch. That's the mechanics.
I've been able to kill him (most of times) when he was under Wat's buff (I used the all jedi GLuke squad), sometimes even when he was under Bastila's lead and/or Hoda's Matser training

in 3v3, GAS can also kill JML because his offense keeps stacking, and the same with SEE, because his mastery and because of that his offense keeps stacking