Hi,
Sorry for the issues you are having. I can help troubleshoot this with you.
The AJAX is not new it has been around for over a year.
Looks like your sidebar was added inside a custom event template and so the ajax reloads the whole div it loads the sidebar again.
I would look into putting that div outside of the events div:
#tribe-events-content-wrapper
You could also back out any customizations and change your Event Template here:
Events > Settings > Display Tab
Then change this setting or another setting:
Events Template to Default Page Template
And see if that helps.
Thanks