Repeatable custom field inside repeatable group don't save properly #1035

I created custom field based on the address field

Expected Behavior:

• The data need to be saved properly, each field created need to be saved.

Actual Behavior:

• When adding repeatable custom field, say 3 for example, after save I only find 2.
• If there are for example 3 fields, and I added 4 other fields, after save, I only find 4 where the total should be 7
• Sometimes it will save all fields except the last one
• Saving doesn't work properly in general.

Steps to reproduce (I have confirmed I can reproduce this issue on the trunk branch):

1. Create New Post
2. Scroll to Book details metabox,
3. Create 3 fields (or any other number), give them random names
4. Update post (you'll see that only first 2 fields were saved)
5. Now add another 3 fields and update (you'll see that only the first one of them was saved)
6. If you add another group it will act the same way

I suspect it's javascript bug.

CMB2 Field Registration Code:

https://gist.github.com/bomsn/36174de42bfbaa74abcd5bce1bfc432d