go to about:config, and set layout.css.resizeobserver.enabled to true
Version 68 is the current 'extended support release' and is used on some clusters (which is why I was affected by this bug). ESRs are maintained for 'more than a year' and 68 was released in July 2019, so probably there should be a new one in the next few months, then the issue will be resolved. https://support.mozilla.org/en-US/kb/firefox-esr-release-cycle
Known bug with matplotlib https://github.com/matplotlib/matplotlib/issues/18481
Is only an issue with Firefox 68 (which is still the version on Freia). Workaround is https://github.com/matplotlib/matplotlib/issues/18481#issuecomment-692337027
Version 68 is the current 'extended support release' and is used on some clusters (which is why I was affected by this bug). ESRs are maintained for 'more than a year' and 68 was released in July 2019, so probably there should be a new one in the next few months, then the issue will be resolved. https://support.mozilla.org/en-US/kb/firefox-esr-release-cycle