- Question posted on Programmers (let's call it Q1),
- Same question posted on Code Review (let's call it Q2),
- I migrate Q1 to Code Review,
- Someone notices that Q1 is a duplicate of Q2 and votes to close,
- I notice the duplicate notice and the auto-generated comment and also try to vote to close, but can't. No error message, nothing, it just doesn't work.
And then I notice that Q2 no longer exists ("voluntarily removed by its author"). My guess is the OP also noticed the duplicate vote, realized how messy cross posts are and decided to be a good citizen and delete one of the two questions. He picked the wrong one though, and now we're left with a duplicate notice pointing to a non existent question and an unresponsive dialog.
It's a mess ;) A weird and rare mess, but still a mess. What can we do about it?