Think it should be 'one way' only?

You got the right idea Kamaro. Many times I would do swaps with the WAV Convert, and other samples in banks and or songs would have these bursts of unrelated samples in them afterwards. I blamed all that on my lack of ASPI.dll at the time, and since all has been....fine?
I think what I'll do from now on is if a sample has to go from the 808 to be 'tailor fitted' or stretched - don't bring it back into the 808, and just trigger a 'soft sampler' with the new improved .WAV et al.

But what a pain!