There is a few things you can try. One have you tried restarting the game? this could reset the controller for you so that if you moved the analog during loading the controller is not reading as walk ( insert direction) when you don't want it to.
Second you can try re powering the controller itself since this also resets the controls being read by the cloud.
The Third is you can try changing your wifi connection type. It is know that 2ghz connections exp more issues than those using stadia via a 5ghz connection.
Another note is your internet speeds and internet allocation. If you plan to play stadia you may want to enter your router settings and allocate a dedicated amount of resources to the stadia over other devices. This helps to insure stadia receives the speed necessary for an adequate gaming exp. most people can reach their router by using a computer on that network and typing in your Ip address (please note this does not work for all routers).
I contacted stadia support and open a case. They were going to check the game itself since there's audio and lag problems too, which I'm not the only one whit this issues. I mostly play on my TV with lan cable 400-500 mbps. The controller get disconnected from the game since I can still jump to stadia menu or screenshot. In order to get out of the game I have to turn off the stadia and jump back in, by the time I manage to get back in I can't join previous group. Support asked me to try another game just to rule out problems with the server.
I have multiple business accounts that make up the internet of my house with the stadia, my gaming pc, and my laptop all having a dedicated gig of speed per second to each device at all times. I have top of the line router and modems as well as plated cat 6e cables. My net is not throttled and I do have symmetrical system as well. Being that this issue only persist in the stadia serve as I have seen this issue even when playing through the browser as well, I believe Stadia has lots of work to do to make it a better place to game. Instead of shifting blame to developers, The management of Stadia need to put serious work behind making stadia a great place to play. I think it's also sickening that the raid for Ghost recon has been out for three months and we have a version of the game that does not have it. On top of this there has been no updates for the game since it's release on stadia. This is true for other games like the 2K games excluding NBA 2K20 which gets updates for player rosters and new myteam cards but not for issues concerning the actual game.