Having the same issue.  Its almost unusable for us.  Takes forever to open an invoice now.  Then when closing, takes us back to the home screen.   So frustrating.   Doesn't work in Chrome anymore - it's been happening for a few months now.  Using Firefox, but its happening there too.   And we use private mode all of the time - there is no cache.  Just to be sure, we hard clear it CTRL F5.

Gonna have to switch to Stripe.  Its just unbearable at this point.  Bringing up dev tools in the browser shows a ton of warnings and errors.