clazz.isAssignableFrom will return false for interface implementors

A DESCRIPTION OF THE PROBLEM :
I create an web application on tomcat server with spring framework and hibernate validation.
I have an interface which define method with javax.validation Annotations.

We use Hibernate-validation to check methods:
executableValidator.validateParameters(target, method, args);

see https://github.com/hibernate/hibernate-validator/blob/7987755f0617504b567f2a5a0437d8695659e4ce/engine/src/main/java/org/hibernate/validator/internal/metadata/aggregated/rule/MethodConfigurationRule.java#L73-L77

Sometime we will get the wrong result and a ConstraintDeclarationException is thrown.
I checked that all use same classloader. This also happen with debugger but if I evaluate toString for one of class the result will be correct.

With 14.0.2 I didn't see this behaviour. After Upgrade to jdk15 this will occurs often after restart the server.

 that implements i

REGRESSION : Last worked in version 14.0.2


FREQUENCY : often