I tried a title command in 1.8, then the same one in 15w41b. It worked in 1.8, but not the snapshot. The error in the command block says "Invalid json: malformed JSON at line 1 column" In 1.8, all three commands activate, but in the snapshot only the last one activates. I am not aware of any changes to the title command in the snapshots, so I am not quite sure why this isn't working.
Dupe of MC-83460. Quotes are now required around the keys.