I am an end-user that has been using roundcube for many years in numerous unrelated instances and have never seen this weirdness before. Here's what's happening:
For the last several weeks a name in the From field will sometimes be replaced by a random unrelated word. The same random word seems to be be "attached" to that user because it is always the same word but it comes and goes. This has only happened to two members on a mailing list and the words that have popped up are "sour" and "Evolved".
It looks like Roundcube Webmail 1.2.3 is installed plus these plugins:
filesystem_attachments 1.0
jqueryui 1.10.4
password 4.3
Has anyone reported this before? And is there a fix for it? It's not critical but it would be really annoying to have to remember which user is attached to which word if more of these substitutions pop up.