Group initiative not working

[CarlNelson]

When I go to add them via the group numbering icon to combat, I get this error in console

And it doesn't add numbers to the combatants nor add them to initiative. I can separately add them to initiative and then add the numbers but they're not grouped in initiative.

[CarlNelson]

A video of the interaction that isn't working

Group.Initiative.not.working.mp4