I am Stadia user since the beginning and own almost every game. That's why I notice more and more that patches or content are missing. Here, a list.
https://bit.ly/StadiaMissingContent
Checking patches is time consuming. Who likes to help, gladly.
It is unfortunate that some releases on Stadia are not on par with other platforms. Hopefully the devs will pay more attention to this in the future and make sure their game release on Stadia will not fall behind other platforms.