CR55DAN

As titled, p187F position deviation on the auto trans fault code, any ideas what this could be? Audi A4 Avant quattro

Hi all, new Audi owner here and can't find the answer I've searched everywhere for. To the point: I've purchased An A4 Avant 2.0 TDI quattro, and seem to have a strange noise when accelerating in 4th, it makes a noise before it goes into 5th, both in manual and in D and in S mode. S mode it seems louder more aggressive noise. I've just had the gearbox service today hoping it would cure it, it hasn't. The noise only happens going from 4th to 5th, but not the actual gear change itself, it's before the change like a pre selection, I suspect something to do with how it swaps from one clutch to another, but only does it from 4th to 5th, and 6th going back into 5th. I'm puzzled and can't find anyone with similar issues. Any help / advice would be appreciated.