Yes and no. In our particular setup, with a Planet T5 tx and rx set on one side of the mixer and the tz85s on the other, it so happens that it's not perfect. But it isn't what I'd consider an issue, at all. I have never noticed the oddity in the arena across the 30 odd battles Tormenta 2 has done.

We didn't get it from this seller, but this is the model we have: http://www.ebay.co.uk/itm/GWS-V-TAIL...item20c29a50cf

In Tormenta 1 we ran an identical setup to the one we have now, but with Electronize instead of the Botbitz, and the oddity wasn't there, so chances are it's something that can be fixed anyway.

For at most 10 quid, it's worth a shot?

Edit: as for "don't people have issues..." I can't speak for others, but I don't think this is a common problem with mixers.