Since phpBB 3.2.1 (and perhaps phpBB 3.2.0 too), the value generated by the template variable {NOTIFICATION_TYPES_COLS} - used in ucp_notifications.html - is too high. For example, its value is set at 4 instead of 3.

There are drawbacks with 'excessive' colspan (even by an extra unit) for a table cell. Some browser (at least Google Chrome) don't properly well the right border of the table. The visual bug is minor in proSilver but possibly more apparent in other styles. Compare the screenshots (the one with colspan wrongly set at 4, the second with colspan set at 3). It's not a big deal at all, but it's still a graphical bug.

An excessive colspan can create other potential issues (imagine a style designer who would like to change the table-layout, there would be problems due to the 'fake columns' generated by excessive colspan). For more information, see https://stackoverflow.com/questions/27874719/what-is-the-potential-drawback-in-using-excessive-colspan

Please note phpBB 3.1.11 is not affected by that issue.