It doesn’t appear to be a cud, it looks like a very minor planchet flaw. Not likely to be worth more than face, but still a cool find. Are you using magnification when you’re searching for errors, or just using your naked eye?
Mostly with my naked eye. When I see something on the coin then I'll use magnification to see if it's just damaged or not.
It's a Mint error. If memory serves me correctly, @paddyman98 wrote a thread on this early last year.