[Hummingbird] Trouble adding multiword user agents

Hi, all.

I am currently using a theme which redirects mobile users to a different page whenever they try to access the front page of my site. The redirection stopped working as soon as I turned Page Cache on, so I reached your support.

I was kindly informed that, while Hummingbird still can't handle mobile users differently for cache purposes, I could add user agents to a list where they'd be served uncached pages. That's good enough for me, I tested it and it seemed to work.

A couple of hours later, it suddenly stopped working. Now, whenever I try to add an user agent, every space between words becomes a line break and so the user agent isn't recognized anymore.

Any thoughts on why that might be happening and how to fix it?