I'm also having to fix things with a symbolic link, so far for both:
I'm only just setting up roundcube so may find others. I can see
/var/lib/roundcube/plugins/ has also (with a - in them):
All five of these use _ in the main .php filename.
- Athanasius = Athanasius(at)miggy.org / https://miggy.org/
GPG/PGP Key: https://miggy.org/gpg-key
"And it's me who is my enemy. Me who beats me up.
Me who makes the monsters. Me who strips my confidence." Paula Cole - ME