I have discovered that all game rules have ceased working. As you can see in the many recent issue posts, gamerule commandBlockOutput is not working. What I have also discovered is that any value can be set to a gamerule, for example, the following command passes as true, and stores the information to the gamerule.

/gamerule doDaylightCycle Dinnerbone

If you then type:

/gamerule doDaylightCycle, you will recieve the output of

doDaylightCycle = Dinnerbone.

Your humble player,
Weaversam8