Now, I know Turn Signals On A Land Raider started off as a little independent blog cartoon but it is now part of the official GW establishment and features on Warhammer-Community.com..
Artistic licence by the creator perhaps but following on from an Imperial Standard mention and an official Praetorian Astra Militarum painting guide is this:
https://www.warhammer-community.com/2019/11/08/no-33-cavendish/
Those characters used to be illustrated as Cadians.