Verified in 6.1.8 Compose 1
when restrict_composite_view = 'true', user cannot promote to any environment of which the contained content is not already a member, and an appropriate error message is thrown
when restrict_composite_view = 'false', no such restriction exists and promotion is allowed.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.