Thanks for the report. I confirm I have now tested this with a Demo account and I get that same message. It looks like no-one tested that "unlock" with Demo account before the recent release. Actually you only get that response if you have entered the correct user name and password, and there is no real effect of unlocking the Demo, except to confirm your user name and password.
So... sorry for the misleading message, but it does mean you're good to go with the Demo. And the actual unlocking, for S1, S2, S3 licenses does work correctly!