On meta.stackexchange about an hour or so ago, this happened. Normaly encountering an off-topic post I would flag as "Should be closed" which directs me to a number of options: Blatantly off topic, should be on another site on the network etc.. but this appeared as the flagging options:
Of course when I flagged for mod attention stating "off-topic" as the reason, my flag was declined with this:
Has one of the "standard flags" - the "Should be closed" option been removed, or is this a quirk of some days in early april?