Please have a look:
http://www.plantuml.com/plantuml/uml/SoWkIImgAStDuKhEpot8pqlDAr5G0Z4TbHGIYnN0B8LgBavE1KKmEpwn9DunmDD8mHQc34FE45ckbekB4yra9xZ9JaWcEw7hTiBKxLXG0DOBfA4wWIoGFcUN-51F1Lk82eG4mgb0BjGuL5_OsEZgAY2fjL80aQYg31M0Qb2SQAKG7PrHKb9WfQzVNbwkbvwVdvwJgWTKeW2IZOtbSaZDIm66AG00
It worked fine in plantuml.1.2019.10
(--------)
It work if you add "":
http://www.plantuml.com/plantuml/uml/SoWkIImgAStDuKhEpot8pqlDAr5G0Z4TbHGIYnN0B8LgBavE1KKmEpwn9DunmDD8mHQc34FE45ckbekB4yra9xZ9JaWcEw7hTiBKxLXG0DOBfA4wWIoGFcUN-51F1Lk82eG4mgb0BjGuL5_OsEZgAY2fjL80aQYg31M0Qb2SQAMW51sTKL9IOAMlNrvUhfUUdv-Uawe7LAC0aewDLU9oICrB0OOg0000
I think that it should be just fixed in the latest version, shouldn't it?
I am not the developper, only a user. So I cannot answer to this question, sorry