Gradients felt on bike too early?

Just done Richmond in the WTRL race - something definitely odd with the gradients being presented about 5 secs too early on the bike. Especially noticeable going up ‘Abby?’ - the very hilly bendy part towards the end. Spinning the legs yet screen says 10% :arrow_up:

Wifi and BT. Just installed 5Ghz 800Mbps Mesh hubs around the apartment and getting blazing speed and ping times - so not that.

Zwift running on 4K Apple TV with bike connected directly (within 3m).
Companion App on iPhone 12 on same wifi.

Anyone else?