Hi Chris,
Thanks for reaching out!
I just tested this out on my end, but I am still seeing related events, even when the event has passed. Can you try updating to the latest versions and see if that fixes this for you? If you don’t see a prompt to update in the Plugins section of your Dashboard, you can do so manually by following these instructions.
The Events Calendar: 4.6.7
Event Tickets: 4.6.2
Event Tickets Plus: 4.6.2
I would also recommend testing this out in a default environment (default theme and all other plugins disabled) to see if the related events show up for you there.
Let me know what you find!
Thanks,
Jennifer