wp invoice/quote not calculating and deferring to inbuilt template

Hi
I can’t be certain when I noticed this and it might be an update issue or the fact that I’ve been trying to improve site speed etc. I’m going through the process of disabling plugins now. However, I raise the issue as sometimes it prompts others to chirp in. My quote no longer and transforms into an invoice. It states “something went wrong”. To add to my confusion it now processes the quote on the unified template, rather than the page I told it to process. The same page it has been using for years.

mark