That’s a bug in the constraints on Wikidata – “date of birth” has a constraint stating that its value must be at least 30 years away from the “date of birth” value. We’ll work on resolving this (I contacted Ivan Krestinin, who added this “experimental constraint”, to ask if he still needs it – and if it can’t be removed from the P569 talk page for some reason, we’ll probably filter it out in the user script).

Hi!

In the past few months, the development team has mentored a student,
Olga, to help us developing a user script
<https://www.wikidata.org/wiki/User:Jonas_Kress_%28WMDE%29/check_constraints.js>
that displays the constraints on the item pages.

This is awesome. Thanks so much for developing it!

Now, is there a place to submit bug reports? :) I have noticed this one:
https://www.wikidata.org/wiki/Q5066005#P569
shows 2 violations, though the date appears to be completely fine.