Yes, I agree Mike. I think it’s a bug in switch_to_blog() that doesn’t load in the setting for the tags permalink of the blog you’re switching to (seems to stick with current one – but not really tested in depth – certainly /blog/ (which is it seems to be using) looks ‘hard wired’ into the root blog). I guess I should report it, but still new to this, so didn’t want to rush in and embarrass myself.