After blocking (right mouse) - the game frequently gets into a state where mouse buttons no longer work and the character becomes immune to enemy strikes.
https://stadia.google.com/capture/7516e921-53a8-46e7-ad7e-c37d92bd1bc9
Wow... That looks like a really annoying bug!
I've had a search and I can't find any other reports of this issue, so it doesn't appear to be a common bug. As it's a bug in the game, you're better off contacting EA support as they're the ones who can fix it rather that Google.
Good luck getting it fixed!
Honestly you're going to want to use a controller to play this game regardless, the controls are janky enough without trying to shoehorn it into M+KB controls. If you can get through this game on any difficulty beyond "Story" with a mouse you're my hero. I'm nearly through it myself using the Stadia Controller and other than the timing being borderline unfair I haven't run into any issues where it just flat out ignored my inputs using that method, at least.