Well, if you rotate the 10x10 px slice without scaling, you can see the bleed on your output still, even with pixel perfectly aligned slices.
In v5 you could choose between tri-linear and nearest neighbor scaling in preferences. Resolume now uses tri-linear on the output (since v6). With the nearest neighbor mode, the bleed doesn't seem to happen in 5.
Switching back to nearest neighbor scaling would have pixelated scaling results, it could be worse than having 1 px of bleed.
If you'd need to choose, - and as this hasn't come up in the few years where Resolume 6 an 7 was out, - I'd guess the bleed is a lesser issue than pixelation, right?
240x200px slice scaled up to 1080p: