Do liquids continue to "boil" when full-pressure cooking is reached? Liquids in a pressure cooker can reach higher temperatures because the boiling point increase as the internal pressure rises. 

But do those liquids continue that "rolling boil" once the cooker is up to full pressure? Or does the increase in pressure keep the liquids from continuing to actively boil?

Background: When I cook meats in a pressure cooker, I place them on a cooking rack to keep them from being submerged. I was wondering if the liquid is boiling enough internally to effectively baste the meats in that froth.

I am using an Instant Pot electric pressure cooker which reaches about 12 psi.
For as long as it is plugged in and the power setting is appropriate, it should keep boiling as if it was in a normal pot. Imagine if you were to take a normal pot deep underground where you get the same atmospheric pressure and watch it boil, it would look the same as boiling as sea level.

It is the water vapor that sustains the higher-than-outside pressure inside the pot. The lid has a valve that impedes the release of vapor. So, without continuous boiling, pressure would decline gradually (like once you turn off the pot).