It depends strongly on what you count in here. Major Bugs seem to occur rather seldom with the current Big Sur version on M1 Macs from my experience, although they definitely DO occur (e.g. Kernel Panics leading to reboot, or Boot Errors rendering the machine useless until forced reboot, or iOS/iPadOS Devices not being able to communicate with Finder).
In contrast, minor bugs occur extremely frequent on macOS 11.2.3, at least from my experience on M1 MBP with external screen. Much more frequent than e.g. on average Windows 10 Installations. Took some notes about reproducible OS caused bugs and am now counting 43(!) of them in 11.2.3. For sure there are many more bugs in the OS which I don't recognise in my daily use, but from these 43 at least the vast majority is caused by macOS exclusively.
If the question aims more on if there are flaws in 11.2.3 which are not present in earlier 11.1 or 11.2ish versions, the only thing I recognised here is the absence of the startup chime in most cases although selected (which is a rather insignificant bug compared to the other 42)