[SOLVED] Firefox 77.0.1 (64 bit) - no vertical scroll bar

On one particular site https://www.telegraph.co.uk/ the vertical scroll bar only appears as the page is being refreshed and then dissapears, so I cannot scroll the page, no bar to select and the scroll wheel doesn't work either.

Linux Mint 19.3 64 bit

It works fine in Chromium

Any ideas folks?

BTW I've posted this on the mozilla support page
https://support.mozilla.org/en-US/qu...answer-1333629
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