The dalton conversion factor to kilograms in the knowledge base is not up to date.
SI Brochure 9th v3.02:

Value in https://si-digital-framework.org/SI/entities#units_20260303103151Z.ttl:
...
si:hasNumericFactor "1.6605390666e-27"^^xsd:float ;
si:hasNumericFactorAsString "1.660\\:539\\:066\\:60(50) \\times 10^{-27}"^^xsd:string ;
...
The dalton conversion factor to kilograms in the knowledge base is not up to date.
SI Brochure 9th v3.02:

Value in
https://si-digital-framework.org/SI/entities#units_20260303103151Z.ttl: