After more testing it seems the Tags module on the right of a New Event post is tied with the Edit Post capability for the Roles permission. So, if someone is running into this same issue, it can be “solved” by Granting the Role the ability to Edit Posts (Posts > Edit Posts > Grant). Though I believe this is still a bug, it may be due to permissions within WordPress itself. Would appreciate any developer feedback on this. Leaving it open for now.