No, that is not an Early Access build - it is in fact the latest Production build…
And your screenshot of the Web Administration Interface page shows that you have an old build (1234) of the Roon Server on your ROCK.NUC - that’s why you are being told that you need to update it to build 1413.
I don’t know why clicking the Reinstall button on that page is failing to update the Roon Server - are there no error messages? And you have tried rebooting the ROCK/NUC, right?