Kanban board filter that only retrieves sub-tasks doesn't work when sub-tasks use a different workflow than the parent issue

Steps to reproduce:

• Create a new project
• Create one workflow for the regular issue types and another workflow for the sub-tasks issue type. Associate these workflows to a workflow scheme, and the workflow scheme to the newly created project
• Create one issue and several sub-tasks to it
• Create the following filter:

parent = TST-1 ORDER BY Rank ASC

• Now, create a Kanban board
• Change the filter associated to the board to the one created before
• Now, try to drag the unmapped statuses from the workflow associated to the sub-tasks to the columns. Once you drag the first status, all the other disappear. The status that was just mapped will be displayed with a next to it. when putting the cursor on it, the following message will be displayed: "This status is not available in any of the workflows used by this board. To remove, drag it to unmapped statuses where it will no longer be available."