The rare double identical comments. That has happened to me too a while back, I think only once for me in the past two years or so.
I'm guessing you made the comment on a cellular device that can also connect to the internet via wifi. Your device was probably switching between networks when you tried to post the comment, you got an error message and generated again.
If you download both picard wtf images, they have the same file name. One of the strange rarities you see on imgflip....
