Hi,
Thanks for using our plugins. I can help out here.
I tested this out and I see it is an issue as you describe for WooCommerce Tickets.
RSVP tickets do show on the sub page for me.
Thanks for doing the conflict testing as well to narrow this down.
I have created a ticket for us to address this issue, but do not have a timeline when it will be fixed. WE usually do a release every 2 weeks for bugs or for major release.
Also, I changed the wording to sub page in your post as that is what WordPress calls it and to not confuse with the taxonomy category.
Let me know if you have any follow up questions.
Thanks