Unable to remove labels on Pull Requests

On my Github account (which is assigned to an organization via SSO) I am currently unable to remove labels from Pull Requests.
When I click on the small X next to a label nothing happens.
The cursor initially is a standard “click” cursor, after clicking X once, the cursor stays as the standard cursor

Other users in the organization can remove labels with no problem, but I can’t. I’m using Firefox and see this issue in the console:

I’ve tried using different browsers, different computers, restarted, signed out and signed in again but to no avail. Does anyone have any idea what might be the issue?