I have noticed that some records in Wikidata are using a site trismegistos.org to establish birth dates. This is giving some odd results!

An instance is here

date of birth
1999
1 reference
reference URL http://www.trismegistos.org/editor/7726
named as Jill Harries
retrieved 9 October 2017

Is it possible to change this behavior?

[apologies if I am using lax terminology, or if this is not the best place to ask]