The bug has been found in these browsers:
The bug does not appear in these browsers:
The table cells containing 4 and 5 get rendered with a heavy (3px red) border-bottom, but the CSS specifies just plain "1px solid #bbb".
If the "bot" class is removed from the cell containing 3, then the problem goes away.
The border-top of the cells containing 4 and 5 seems not to be affected by the bug.
This bug has been reported to WebKit Bugzilla.
First version: 15-Nov-2016 Updated: 12-Dec-2018