I believe it was zero at the time (since that's what it is now). However, I think it may have had a border (due to forgetting a step in my manual post-processing explained below) (Edit: It did have an impossible border, as a side effect of my manual bleeding issue fix + forgetting to clear border as one of the steps)
I should mention there is one thing I'm doing that might be a bit unusual (but still within reason I think) and possibly related to this bug:
I have a sprite that was intended to be 64x64, but since it is stretched across the whole screen, neighbor pixels (usually transparent) kept bleeding in at the edges (due to linear filtering). So I instead made it 68x68 (using "Add a Clamped Border") and then every time I update the Atlas, I have to re-add the clamped border, and tweak the dimensions for that one sprite.
Those tweak being (under "Dimensions") +1 to X, +1 to Y, and -2 to Width, and -2 to Height. Effectively making it a 64x64 sprite again, but with similar pixels outside that remove the blending issue.
Slightly more off-topic for a moment: I'd love a way to have NGUI do my currently manual process. "Add Clamped Border" is close, but uses "Border" gives the wrong behavior for what I need. I may end up just putting those touchy sprites in a separate atlas for a while, so I dont have to keep re-applying the dimension tweak when adding/updating other sprites.
