Click Cancel next to the date the invitation was sent. If you don't see Cancel, it means that no further "Email Invites" are scheduled to be sent to that contact.
Shane K. [Nextdoor Rep]
If you invited friends via email we do send them the initial invite and then two follow up reminder emails. If for some reason they are still getting these reminder emails please let us know by contacting us here: https://help.nextdoor.com/s/contactus?language=en_US
Interesting damage control. You shouldn't have to turn this off when you never turned it on to begin with. Nothing should ever be sent out from your account without your explicit consent, period! Use your own imagination as to why this is occurring.