Section 4.4.5. Group conversion of the spec is described as follows.

@ConvertGroup and @ConvertGroup.List can be used everywhere @Valid can be used (associations, method/constructor parameters and return value). If these annotations are used without @Valid, a ConstraintDeclarationException is raised.

But @ConverGroup and @ConvertGroup.List target TYPE which @Valid does not.
So, remove TYPE from targets of @ConvertGroup.