So I have had the same problem.
When you have a group element if you delete one of the elements that is not on the end, it saves it back to the database it uses an associated version of the array and therefore it doesn’t reload. The good news is that in the database you can fix this.
when the item gets deleted this array uses the associated version and not the indexed version. Hopefully this is making sense.
Ie
something like
[
0 = > ‘test0’,
2 = > ‘test2’,
3 => ‘test3’
]
THE FIX
Go into your database find the element convert it to array, and replace the 2, and the 3 with a 1, and a 2 respectively or what ever is your database, and then re-serialize it and it should resolve the problem.
THE TEMP FIX
Move all elements to be deleted at the bottom first before removing.

I think this is in some kind of bug list, but not 100% sure, as there has been similar issues, but not exactly the same.
I hope this helps.
Regards,
Shawn