The example code is wrong..

public void produce(@RequestScoped Something instance)

and

public void produceQualified(@Qualified Something instance)

are not valid producer methods. I suppose it should be more like this:

@Produces @RequestScoped
Something produce() {
...
}
@Produces @Qualified
Something produceQualified() {
...
}

Nevertheless, this is a Weld bug - the @Default qualifier is not assumed if no required qualifiers are specified explicitly (the first disposer method).

Also Matus Abaffy's workaround works.