Yep, more playing.
It doesn’t seem to be the type of text that’s in a tab name (drive letter or folder name) but that once you start dragging a tab, all other tabs shrink to display just the text and nothing else. So my max size tabs of 175 means even if it shows C:\ or Computer, all the tabs are the same size. Once I start dragging a tab, that C:\ tabs shrinks so only C:\ shows with no extra space. Computer shrinks a little too. So if the accidental dragging on clicking/selecting a tab is the cause and you have max size tabs like me, the new spot (where the mouse courser started and ended) is now further to the right so once the button is released, it looks like the tab jumped to the end.
This can also happen with no max size set to tabs but still having “same size tabs”. If you have C:, D:, E:, and Computer open as tabs. Computer is in spot 2 and you drag it to move the tab, the remaining 3 tabs shrink a lot since Computer is I guess not considered in the size anymore. Drag Computer that’s in spot 2, only move it a few pixels to start a drag, now let go, it goes to the end. Because the 2 tabs to it’s right got smaller in size.
This only is true if the accidental dragging is accruing though. Still just my 2 cents
Ok, I’m done testing