Hi, this will be tough to analyze without some more details. Can you narrow it down to a specific method / type to be validated? Is there a class hierarchy, with interfaces, involved possibly? It'd help to see a type whose ParameterMetaData sometimes contains the constraint metadata and sometimes not.

One possible issue I can see is overridden methods, where it might be that constraint metadata is getting lost during merging the data from the different methods of the hierarchy. We used to have issues around that, though they should be solved by now. But maybe it's some corner case related to that. Just an idea, though.