I recently happened across this gem of a question, and noticed that Ken White had already done much of my work for me by writing an extremely comprehensive and detailed close reason. But when I tried to piggyback off his labors, the system shot me down—repeatedly:
I've tried again…and again. Doesn't work.
I'm guessing that it is somehow related to that custom off-topic reason, because I have been successfully voting to close other questions on SO and Meta.
I've been hesitant to try closing this one for a different reason in case I need to demonstrate that the problem is reproducible.