Hi,
Following on from my Facebook Group message - please find details attached.
To recap the problem:
I have tried it on my site though and works perfectly accept that I think it has conflict with my theme, Enfold.
With Rank Math installed my checkout and cart pages are no longer mobile optimised and I am unable to fix this apart from deactivating my Rank Math plugin.
I can also no longer build pages on the backend and make them viewable on different screen sizes.
When I deactivate, the problem goes away.
I can also confirm I have used the required Health check and confirm it is a plugin conflict as far as I can see.