Additionally, in order to debug this issue and to minimize the cause of the issue:
Could you please try to resolve your issue by deactivating all third-party plugins as well as the default theme to check for any possible conflicts with any of the plugins or themes?
Also, I see there is a couple of ways the site is caching the things. Can you please sure that you disable all caching.
I have tried temporarily disabling all plugins except the 5 Toolset ones but same thing happened. Have also temporarily disabled and purged all caches and still not playing along.
It was a merge since the live site was still accepting updates so I couldn’t use the plugins you mention and instead used the Toolset Export/Import tools. I also find/ replaced URLs.
Ok - I checked on your install by creating brand new user form and added to a new page and also grant permission to Guest users from access control but still as a guest I do not able to see the form on frontend. Then, I also tested with my local test install where only Toolset plugins active and I do not able to reproduce the issue.