Drop-Down flickering with preexisting values when assigning a developer on a board to an issue

Summary

The searchable dropdown list renders twice, when a value is already given. First to render all suggestions, later to render suggestions filtered by the given value.

Steps to reproduce

1. Open the board.
2. Click on an issue.
3. Assign a developer and for that, filter by name.
4. Click on another issue.
5. Assign another developer.

What is the current bug behavior?

The searchable dropdown list renders twice, when a value is already given. First to render all suggestions, later to render suggestions filtered by the given value.

What is the expected correct behavior?

It should only render once, with the values already filtered.

Output of checks

This bug happens on GitLab.com

Possible fixes

When first rendering, check if a value is given and filter before rendering.