I heard Vincent D'Onofrio use the words out of nowhere

TV You might remember how, during A Christmas Carol, this year's Doctor Who Christmas special episode, my emotional investment was tainted by having all of this stuff about the series rattling around in my brain. Kyle Anderson at Nerdist has written a far long article on the topic, explaining in some detail the origins of the "Blinovitch Limitation Effect” in the fiction of the series and why some of us were so perturbed first time around:

"In the 1972 story “Day of the Daleks,” a concept is offered up to explain why it’s a bad thing for a person (or object) to physically interact with itself should it travel in time and cross its own timeline. Should one do so, they would cause a paradox resulting in the destruction of the universe or the sudden death of puppies or something else awful. The fictional name for the concept the story’s writer gave is the now-famous “Blinovitch Limitation Effect.”

So ingrained a piece of Who-lore is Blinovitch, it's even been employed or homaged in non-Who texts such as Brad Anderson's Happy Accidents (and imagine how excited I was when I heard Vincent D'Onofrio use the words out of nowhere in this US indie film which is about a hundred miles away from Saturday teatimes) (other instances are included on the theory's (oh dear lord) wikipedia page).  I once also heard someone using it in an argument against time travel as though it was real thing with a scientific basis.  I didn't correct them.

Doctor Who, with its nearly fifty years worth of continuity baggage will inevitably contradict itself and that's ok.  It should.  Elements are established, re-examined and established again with each new author stamping their own identity on it.  Only a small number of viewers proportionally will have cared about these things and it's only our geek training which causes us to bawk when one bit of fiction contradicts another even if it has nothing to do with the story at hand.  Just relax and enjoy the adventure.  Barring cheap tricks.