Did something happen with CSS files after updating Radzen on Sep 15?

All at once my buttons are the same color and larger (I have them marked as small). Also the grid headers are different and has small alignment issues.

I didn't make any of these changes they just started appearing after updating yesterday.

There is no Radzen update on Sep 15 - most probably you've updated manually Radzen.Blazor? Check this thread for reference:

enchev is Radzen Blazor Studio ready for production app use?

Radzen Blazor Studio is still in alpha state however we are about to release beta with default security enabled.