Protected Branch Tool - Clicking 'no one' multiple times increments # of roles every time

Summary

Protected Branch Tool - Clicking 'no one' multiple times increments # of roles every time

Steps to reproduce

1. Go to Settings > Repository > Protected Branches
2. Click on Allow to Merge or Allow to Push dropdowns
3. Repeatedly click on No one
4. See # of roles increment

This is on Chrome 62

Example Project

n/a

What is the current bug behavior?

0 roles click no one 1 role click no one 2 roles click no one 4 roles click no one 5 roles click no one 6 roles click no one 7 roles ... ... ...

What is the expected correct behavior?

0 roles click no one 1 role click no one 0 roles click no one 1 role click no one 0 roles click no one 1 role click no one 0 roles ... ... ...

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com