I'm having an issue where the default static flags for new ProBuilder Objects doesn't include Lightmap Static, which it did before. I can't find a default setting to change this, but it's not really an issue, manually checking LMS isn't that much trouble, but several types of PB operations will cause a PBO to automatically uncheck its LMS flag.
As tagged, I'm not sure if this is a bug, or if I don't understand something about the ProBuilder workflow; however this has only been an issue for me since I updated to the most recent Asset Store version of PB.