I entered your image url on https://ezgif.com/speed to change its speed. A speed of 20% works for me. One issue seems to be that the "View Online" context menu option keeps flashing.
It seems that you have several add-ons installed. To identify the problematic one, first disable all add-ons. Then enable one add-on at a time and see if the issue appears. Check if you can reproduce the issue with only the problematic add-on enabled.
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It seems that you have several add-ons installed. To identify the problematic one, first disable all add-ons. Then enable one add-on at a time and see if the issue appears. Check if you can reproduce the issue with only the problematic add-on enabled.