Some places where file or memory sizes are shown use woe-fully wrong units. E.g. for me system monitors’ memory line graph mode will have a Y-axis showing PiB, so the line would be at 9.6 PiB when the legend (and other modes) shows the proper 9.6 GiB used. (This might happen with other system monitor modules and display modes as well… not tried them all)
Another example, having Dolphin show the disk space used (right click>properties) will shows the disk size used of my ssd as being 128 TiB (impressive for a 300 GiB partition).
Somewhere KDE’s “what unit to display” goes wonky.