I've noticed a weird buff, you heal like crazy and your HP and PP bar turn white. It looks like a little blue star. Any idea what this is or how to keep getting it?

It's NOT the techters deband skill.

It's an ARKS Boost that kicks in and increases as the UQ completion rate goes up, just like with the Profound Darkness UQ. Basically, you will tend to see it the longer you are in the UQ and/or the later you start it.

And all 12 man triggers, just like 12 man PD trigger, will start with max boost.