Hi Atlassian Community,
I have a peculiar question regarding my board: the sub-tasks are simply not shown on the board and are not part of the issue type drop-down:

When I navigate to the boards settings, I see subtasks there:

The difference to other issues displayed on the board is the different workflow. Unfortunately I can't update the workflow for sub-tasks although I am a project admin and org admin in Jira.
Do you have any ideas, how to include subtasks on the board?
Thank you so much for help.