Previously working commands borked?

{
    error = 1;
    message = "Command 'on' is not supported. Supported commands: [setLevel, refresh, poll, levelUp, levelDown]";
    type = "java.lang.IllegalArgumentException";
}

Anyone else getting error messages like this when trying to turn devices on or off using code like item.on()? This was previously working for me, but just stopped this morning…

FTR, this seems to have fixed itself as of this evening. Hopefully just a glitch?