Ok, This is a bug... When all credits are removed from the planet, the remainder should be removed and the value set to a true zero (0.0000000).
There is still no chance of data corruption from this, unless you are trying to pull a SuperMan III bank robbery

@Helix, That is not what he is referring to. When all credits are removed and the display reads Zero, there is still some value there (i.e. 0.34629845), which is still accumulating interest. When this value reaches 1 from accumulated interest, a single credit spontaneously appears on the planet.