ATV cadence

Hi
Due to a move around due covid!!! My bike is back in the garage. So I got myself an ex display apple tv 4k.

Works great. Really good, well down zwift.

Apart from the cadence reading from my vortex. Always worked fine on my pc or phone. But on the atv it starts fine and after a few mins starts flicking from 2 values. Say 69 and 96. I can be holding a solid sensible cadence and it if flicking about.

I am sure its not a hardware issue.

Anyone else seen or fixed this?

Thanks

What is the rest of your setup? ATV can only have two (direct) connected Bluetooth devices, so if you have, for example, paired your trainer and HRM, I think Zwift just estimates a cadence. Could this be the issue?

Just the vortex, it has a go at the cadence. So just the one bt connection