I've had same problem, and i think i found a solution for this issue.
When i unticked "sync" on [Out: MiniLab 3 Output (Minilab3 (MID] checkbox row in Live, minilab began to work properly. i've tested it few times, and there was no freeze. I've found no issuies using minilab in this mode so far.
Try it, maybe it'll work for you too:)