For whatever reason, I can no longer create an issue from the Timeline View of my Project and neither can other members of the project.
The image below should clarify the method in which I am trying to create issues from.

I am both a Jira SW admin and a Project Admin for the Project.
I can still create an issue for that project via the backlog, directly from an epic (not on the timeline) and the create issue button, but when creating it from the timeline, I get the following error:
Issue does not exist or you do not have permission to see it."
When checking the permission helper, it confirms that I am able to create issues within that project and that has been confirmed by me creating issues under the same epic that I was attempting to create a story under via a different method.
This issue occurred suddenly while someone was creating issues via the Timeline view -- it was working one moment and then it errored out.
I have tried adding issues from Timelines on different boards within the same project and have the same issue. I do not have this same issue on any other project.
Does anyone know what could have happened or how to resolve this issue?