Hi,
I have exactly the same problem.
Falling back to v64 fixes the problem.
You can find older versions here: https://get.geo.opera.com/pub/opera/desktop/
You also have to stop Opera auto-update to avoid the automatic upgrade to v65, see this:
https://www.askvg.com/tip-how-to-disable-or-block-auto-update-feature-in-opera-web-browser/
Tschuss