Steps to reproduce:

1. Create some item with "Type of information"="Numeric (unsigned)" and Units="uptime" (for example, the standard "system.uptime" metric from some OS template);
2. Create a duplicate item with the same "Type of information"="Numeric (unsigned)", "Type"="Dependent", master item = <created on the previous step>, Units="s";
3. Put to a dashboard 2 widgets with type="Item value" and select for them just created items (default config should be enough);
4. Compare visualization of these items on the "Latest data" screen and on the dashboard.

Result:
See screenshots attached.
"Latest data" screen displays identical values (for example, "00:10:26" and "10m 26s"); but the dashboard does not transform seconds into a minutes for the "s" units: is displays the same "00:10:26" for the "uptime" units, but "10.43m" for the "s" units.

Latest data:

Dashboard:

Expected:
Correct time transformation into a string, as described in the documentation:

s - translated to "yyy mmm ddd hhh mmm sss ms"; parameter is treated as number of seconds.
For example, if you receive the value as 881764 (seconds), it will be displayed as "10d 4h 56m"