Unfortunately I also can't reproduce, so this is pretty mysterious... Does _temporarily_ disabling the antivirus you're using help at all? And could you attach the gif to this bug? The link from comment 1 says "Service unavailable" for me.
Bug 1913858 Comment 5 Edit History
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Unfortunately I also can't reproduce, so this is pretty mysterious... Does _temporarily_ disabling the antivirus you're using help at all?