@James Not shure it's connected with file name, I'm rendering files with cyrillyc names freely. I think, it's renaming files before sending it throwgh the network. Project "таблетки.blend" becomes
"C:\Users\Leo\cr\server\74d13a3f-a36f-4506-9be9-7c3224cc7e51\svr.blend"
Problem appears when the user name (and the name of the system "user" folder) is cyrillic, like
C:\Users\Леонид\cr\server\74d13a3f-a36f-4506-9be9-7c3224cc7e51\svr.blend
I didn't try it on mac systems yet. Not shure about that.