Type of "this" in field initializers & initializer blocks must be the least upper bound of all constructor result annotations

In the lock checker, @GuardedBy <: @GuardedByUnknown.
Consider the following example which has an initialization block.

import org.checkerframework.checker.lock.qual.GuardedByUnknown;
import org.checkerframework.checker.lock.qual.GuardedBy;

public class InitializerLub{
    {
        @GuardedBy InitializerLub field = this;
    }
    @GuardedByUnknown InitializerLub() {}
}

We expect the type of this to be the least upper bound of all constructor types (@GuardedByUnknown in this example). So, the checker framework must report an error at line @GuardedBy InitializerLub field = this; because this should have type @GuardedByUnknown and assigning this to type @GuardedBy is illegal.
However, the command javac -processor tainting InitializerLub.java doesn't produce any warning.
This suggests that the checker framework incorrectly annotates the type of this with the default qualifier in hierarchy instead of the lub of all constructor types.