The "no-source-code" license label is redundant if the license itself is not in the @FREE license group. See the tracker bug 615456 for a longer explanation. Furthermore, the StarUML-EULA license does not grant the right to distribute the software. Therefore, both "mirror" and "bindist" restrictions must be added.
Fixed by: https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=aabd6b709ca5aa53549c9bb5a15b7f18ec4f4f1c