Hi Cori. Sorry you’re experiencing this.
Please follow our Testing for Conflicts Guide (basically switch to TwentySixteen theme and deactivate all plugins and custom code other than Modern Tribe plugins) and see if that helps narrow down the cause of this.
If it doesn’t, please enable WP_DEBUG and WP_DEBUG_LOG and share any PHP errors you see while changing tickets quantity, navigating your site’s home page, events page, single-event pages, and any other of your site’s pages relevant to this ticket.
Then, please share your System Information (while in Testing for Conflicts mode).
You might also see if you can spot any console errors at your site. (If needed, you may reference our KB article Using Google Chrome Developer Tools.)
Let us know what you find out.
Thanks.