1. Set "System Preferences" > "Trackpad" > "Three Fingers" to "Dragging".
2. Using three fingers, drag a tab to change its position in the tab strip.
3. Just after dragging, switch tabs using the keyboard (e.g. Ctrl+Tab).
Result: tabs switch back to their original positions.
This might have something to do with Mac OS X not considering the drag to be "complete" until about a second after I lift my finger.
I'm not sure if this bug predates the fix for bug 455694, but it's certainly more noticeable now that tab dragging feels more like direct manipulation than a mode.
No, it doesn't predate bug 455694. The original fix for bug 455694 had this problem because of an oversight I had. The fix in bug 674925 doesn't have that problem.