I couldn’t figure out who to contact about an error in the wiki so hopefully posting it here will get the job done.
The portion that covers setting up a bridge is inaccurate and will not work. However the youtube video covering the same topic does. Do not turn on Allow Global IP in the zerotier settings for the first or second router.
I have tested it myself and indeed the configuration example in the wiki is incorrect. Thank you for pointing it out to us. We will update the guide shortly.