I'll explain what I experienced today: When the shops reset via the hour cycle or leveling up, I can talk to Arran again. I found out that if I talk to Murga, who is sitting near Effie at this time and also has bugged dialogue, it breaks Arran and you can't talk to him.
Maybe today's patch has fixed this. I won't be able to check for quite some time, so if anyone else can check that'd be great.
Last edited by Zandrake; 06/10/17 04:58 PM. Reason: Patch