Thanks for the report - happy to look into this.
I have a few questions that will help us make progress here. Sorry for the long list but if you can provide this info it will allow us to make quick progress.
What version were you using before? Can you provide the exact build number?
What version did you upgrade to? Is this a beta build?
Can you tell me a bit more about the project? What effects are you working with?
Is the footage C200 raw 4k?
Any third party effects being used? Third party panels or plugins?
Have you used the same project on a non M1 system and seen similar or different behavior?
Lastly, are you interested in providing a project file that I can use to investigate on my side?
Pr Pro Sr QE
Looks like I signed in with a different account. Feel free to respond or PM directly if you would like.