I'm very late to this topic but if you're referring to what I think you're referring too which is the 4 5 and 6 train announcements having the 2 train "The Next Stop Is" Segment, then this was not a glitch nor a mistake. It was a deliberate decision made by the MTA to shorten dwell times in stations. I actually had this concern my self come to realize that it was on purpose. Something else about this is that the MTA plans on doing this to all lines eventually. You might see the N train with the Next Stop segment from the A line. It all comes down to what they believe is quicker. Personally, I find it quite stupid for MTA to really believe that this would some how work.