Long, drawn out “Oh!”
Thanks for that tip Pix. I’ve wondered about that smooth a lot… seems now there’s an answer! 
Ah! Very good info to know!
nypah! there she hides, nice one - albeit a little cryptic! might have missed this one totally, given that i only occasionally bump the render smooth for a check, always taking it back to 0 for modelling …thus my never noticing its effects.
thanks for your insight Pixolator (your name is by no means inflationary!)