It sounds like you may have corrupted your tables somehow - could be a bug but we would need repo steps to track it down. If you find you can recreate the problem you should file a bug report. In the mean time, I would suggest you uninstall the module (you’ll lose all your groups) and then reinstall it, unless you want to start digging through the tables to try and fix it.
As far as using a vmblast group as a destination, sure it shows up as an available destination.