I'm pretty sure I've gotten rid of the cases where this can happen automatically (that used to happen in the earliest version under special conditions), so I suspected Adraius might be on to something with the second labeling and tested it.
It was pretty tough to repeat (for me), but you can get a double label if you manage to mouse over an object within the 1.5 seconds before it gets its own autolabel (but not the reverse, i.e. mousing over an object that already has an autolabel will not create a new one manually). I should be able to prevent this pretty easily, thanks.
Is that what happened, bluemoo?