I believe this is caused by the same root cause of bug 1661222, and bug 1661222 made it more noticeable see bug 1661222 comment 5.
Bug 1662426 Comment 6 Edit History
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I believe this is caused by the same root cause of bug 1661222, and bug 1636728 made it more noticeable see bug 1661222 comment 5. (edited: fixed one of the bug number)