Ok, that explains it!
Even now that you told me, I cannot find it in the manual, I guess because I cannot search for ‘;&’ or ‘&’ alone
And it is not mentioned on the page that explains HOUDINI_PATH either.
Ok, found it, it is on Environment variables page but cannot be found in the main search, only on that page by text search.
So the warning could tell about this & in $HOUDINI_PATH (or have link to that Environment variable manual page), I just copied it from some Octane documentation back then, didn't know what it meant
Of course everyone should RTFM but there is too much to read thoroughly
Anyway, I'm happy now, no messages on start, thank you!
Antti