Moving cards into backlog on scoped board removes scope-label

Summary

When moving a card on a board scoped to a tag back to the backlog, the scoping-tag disappears. So when I have a board "Cheeseboard", which is scoped to issues with the tag "cheese", and move the issue "cheddar" from "to eat" into the backlog, both the "to eat" and "cheese" labels are removed. This is very annoying, as that is an important part of our workflow.

Possibly related issue: https://gitlab.com/gitlab-org/gitlab-ce/issues/37553

Steps to reproduce

I'm certain this can be reproduced more generally, but these are the steps I took to reproduce it in a testproject : https://gitlab.com/tillheinzel/reproduceBoardBug

  1. Create board without any scope (e.g. 'feast'), with list for a single tag (e.g. 'cheese')
  2. Create board scoped to a single tag (e.g. 'Cheeseboard' scoped to 'cheese')
  3. Create card in the backlog of the unscoped board (e.g. 'cheddar' on 'feast')
  4. Move the card into the list for the other board (e.g. 'cheddar' into list 'cheese')
  5. On scoped board, move card from backlog into other list (e.g. into 'to eat'), and then back. Refresh. The card has magically disappeared (eaten?)

For me, the card would consistently have the scoped labels removed. In the original project I did this with team labels, but in the testproject I used project labels

Example Project

This is where I reproduced it. I added a few more lists and stuff just to see if it would happen then as well. https://gitlab.com/tillheinzel/reproduceBoardBug

What is the current bug behavior?

board-label is removed from card together with list-label

What is the expected correct behavior?

board-label should stay, only list-label should be removed

Output of checks

write: This bug happens on GitLab.com