Example:
Put 1000 metal frags in TC
Middle mouse btn half split, half split again. (Stacks of 500, 250, 250)
Right click stack of 250 to inventory.
Click sort on TC. End up with 1000 in TC instead of 750.
Right click stack of 250 to inventory.
Click sort on TC. End up with 1000 in TC instead of 750.