The code section parts following "These Domain Model Validators can also mark some specific properties as failed and add specific error messages:" and (for 5.1+) "Normally, you would need to annotate Collection and Model type properties, so that the collection elements and the model would be validated like this:" are missing.
Seems to affect version from 4.3 on:
https://flowframework.readthedocs.io/en/4.3/TheDefinitiveGuide/PartIII/Validation.html#validating-domain-models
The code section parts following
"These Domain Model Validators can also mark some specific properties as failed and add specific error messages:"
and (for 5.1+)"Normally, you would need to annotate Collection and Model type properties, so that the collection elements and the model would be validated like this:"
are missing.