Hi, sorry for the slow response but the customer just emailed me again on this error, I logged in and now I am gettin git as well. So it is happening when you log in, click components then SP Page Builder then Pages and the error comes up, once you click the button to go back and log back in it doesn't do it. See second test shot from just now showing the full url in the link below
This has been tested and happens in Firefox and Chrome. Please log in and fix it if you can, we have never had this happen so we have no idea of how to fix it and customer is not happy at this point.
https://www.tristatedharma.org/test