Just reading your other post… If your page has changed to PHP, it’s likely because something on the page requires it (such as a form, for example). So it may just return the next time you publish from rapidweaver… Your better off to delete the html if something on your page requires PHP.
I don’t know about all the search stuff though. Maybe double check that ‘indexing’ of your page wasn’t accidentally turned off in Rapidweaver. And I guess check that you don’t have warnings in your Search Console/Webmaster Tools. But ‘search’ isn’t my thing
As an aside, I understand your concern based on what you’re experiencing but I have never heard of php vs html being connected in any way for search…