I was using CMB2 v2.1.2 with WP v4.5.3 and had an issue with text repeatable fields within a group when sorting - the number of the repeatable fields would not move up or down when clicking on arrows. For example if the first item had 2 repeatable text fields and the second item had 3 text fields, after changing the order the second (now first) item would have only 2 text fields and the first would have 3 fields (one empty).
I've made a video to show what was going on exactly: http://recordit.co/COtIqkm5Mf

Then I updated to v2.2.2.1 (also tried 2.2.3.beta) and the same issue is still there but there is also a new one. Upon updating the page, two more groups are added. Next to last group will get the last repeating field value, and the last one will be empty.
Again, here is a video demonstrating the issue: http://recordit.co/Z8VgHU80hT