Okay, I saw similar phantom lines during my flight from Houston to Dallas yesterday...but I saw them when I pulled up the airport diagram (while still enroute), and they weren't vertical. There were two lines, very close together, running from around the middle of the left side toward the upper left corner. They were moving pretty quickly, and within a few seconds had drifted off the top of the screen and I never saw them again. I think they were on the screen for a total of about 10-15 sec or so.
I did not see them (or at least I did not notice them!) in the sectional or weather mode views that I was switching between at the time.