On Liftoff 0.10.3, sorting comments by “chat” shows a full screen grey overlay and does not show the posting or the comments.

(Sorting by chat is also not available as an option when viewing comments, and only shows up in Settings.General)

[FIXED] Edit: appears to be addressed in 0.10.4 in that the option is no longer available. I think this is a reasonable workaround for now.