The 402 stands for an unedited graphics pixel, im sure it doesnt last longer than a second but it can happen in any CGI sequence where theres a frame missing.
Each CGI Model has to move fluently in every part of its body... one tiny miniscule pixel down there on his suit froze for a split second, even a half a second, and the entire code number popped up... for that same amount of time before the pixel refreshed and continued working...
Why no one noticed this before is beyond me.