Support

This is intentional.

The backend shows the total time spent in a ticket. It uses different font and color for hours, minutes, and seconds to give the admin a very “glanceable” overview of tickets sprawling into several hours. At this level of oversight, hours and minutes are far more important than seconds.

The frontend shows the time spent per post. At this level, you're only interested in knowing how many minutes were spent answering to each post. You don't even need to see the seconds (minutes are always rounded up).

Basically, seconds are not important. The reason they are shown in the backend is that an HH:mm display is confusing for anything other than a clock. Formatting something like "1:10" is ambiguous. Is this one minute ten seconds, is it one hour ten minutes, or is it something happening at 1:10 (and is it am or pm)? Therefore, it would have to be formatted either as "1h 10m" or as "1:10:00". The former actually takes up more space and is less clear in all four languages I speak than the latter. The latter is how things are formatted in most sports I have watched when the thing takes more than an hour – with the notable exception of European football which formats one hour, ten minutes, and ten seconds as 70:10, something that has to do with technological limitations in old scoreboards and 4:3 broadcasting twenty plus years ago. But that's another story for another day.