When the police fire at the appearance of the Time Wraith, the bullets pass right through it, yet not one bullet strikes the staircase or wall behind it.
Just before the Time Wraith attacks Caitlin, she looks at her phone because she thinks it's vibrating. Her phone is an iPhone 6. At this point in time in the Flash story line, iPhone 6s had not yet hit the market (as the release date for the episode in which these past events occur predate the release of the 6).