Dear Claudia
Thank you for confirming that it is a known issue (at least to you and me! :-) ) I tried to make a second "footer" module, changed the original to only show on the home page, and the second one to only show on the Privacy Policy page, but got the same result - the Google Maps Add-On still malfunctioned, showing the dreadful "Oops! Something went wrong!"
I can create a "Footer" section on every page, but am reluctant to do so as it will defeat the object of having this functionality on Joomla of having one footer for all pages. And besides, when this site was on SPPB 3 it worked perfectly.
Let me wait for the SPPB team to respond. Hopefully they will have a fix for it. If not, I will have to switch the footer with Google Maps off on all my webpages.
Regards,
Francois