Unity 2019.2 ProBuilder 4.0.5 constant freezes

Whenever I edit a mesh, after a little while the whole thing starts freezing for 10-20 seconds, after every vertex, edge or face is moved.

Scene has a single pipe in it, created with PB, nothing fancy at all. Couple hundred vertices.

Closing and re-opening Unity does nothing, problem persists.

Create a new object, and it’s fine for a bit, until it eventually starts happening again.

And it’s not just a quick jitter, it’s a total freeze, where Unity doesn’t react to anything, and becomes totally unresponsive.

Took a quick gif

anyone?

In the Preferences window for Probuilder, if “Auto Lightmap UVs” is checked try toggling it off.