Second nested form display index incorrect

[solvox]

I added second level nested form and default index is incorrect, i have nested form for Question Model, and inside Question model I have nested form for Answer Model, Questions get correct index: 1, 2, 3 etc but Answers get incorrect ones.

It shoud be: Question 1 - Answer 1, Answer 2, Answer 3, Question 2 - Answer 1, Answer 2, Answer 3
Instead:

On create:
it is: Question 1 - Answer 1, Answer 1, Answer 1, Question 2 - Answer 2, Answer 2, Answer 2

On update:
it is: Question 1 - Answer 1, Answer 2, Answer 3, Question 2 - Answer 2, Answer 2, Answer 2