Hello,
in empty packages in class diagrams, a declared stereotype will be ignored which seems to be a bug:
@startuml
package p1 {
class in1
}
package p2 <<Foo>> {
class in2
}
package p3 {
}
package p4 <<Foo>> {
}
@enduml
http://plantuml.com/plantuml/png/AqXCpavCJrKeC5Ievb9GICv9B2vMoCmpvAhbAe196IdOsBZbvzlPeIWnGbPY39H2qc62fACM0000