Corrected entry: In the scene when John is talking to Mr. D in the diner, Mr. D tells John to "say hello to your old man for me." It is later revealed in season 8 that John's father left them when he was young. This is a mistake, unless Mr. D is referring to John's grandfather (unlikely). (00:04:40)
Hell House - S1-E17
Continuity mistake: Both Sam and Dean show no signs of bodily damage or harm, even though in the previous episode "Shadow," both brothers were attacked and their faces had been slashed by the shadow demons summoned by Meg.
Suggested correction: First part of the episode, it said "2 months ago" below the place where the episode takes place. So it probably took place before episode 16.
Thats before they showed up when the first group of kids went on the house and found the girl hanging.
Bloodlines - S9-E20
Corrected entry: The shapeshifters change appearances in the blink of an eye, but throughout the rest of the series shapeshifters shed their skin and the change takes several minutes.
Correction: The shifter in this episode is of a purer bloodline, so he doesn't need to shed. Just like the alpha.
Where does it say that it is pure bloodline or that a pure bloodline shifts differently?
Corrected entry: When Sam is on the plane searching for the demon, he is told to say the word 'Christo', as demons will flinch at the name of God (said in Latin). 'Christo' is the Latin word for Christ, not God. God in Latin is 'Deus'.
Correction: Since it's a reference to Christian spirituality, the name of Christ is the name of one of the three persons of the Christian Trinity (God). For example, Mary, Jesus Christ's mother, is called "Mother of God" by most Christian traditions ever since the Nestorian controversy (and as the reference is in Latin, the show is almost definitely referencing Catholic Christian theology, which would affirm this).
That is correct and we've seen them use other forms of Catholicism methods and traditions throughout the show. For example, holy water and cross symbols. However, as the show develops we see the main characters begin to incorporate pre-Christian ideologies to fight the demons. One ideology is the actual name of God which the Catholic Church omitted when they used the Trinity to assimilate pagan tribes. Every place where the original Hebrew name for God was had been replaced with 'Lord' and they did the same for Jesus. So terms like 'Cristo' and 'Deus' are titles. Not names. Which is horribly confusing. All in all, the whole "mention God's name and the demon should flinch" then give a title and not a name at all is just pure laziness on the writers and general censorship. In scriptures, usually mentioning the Messiah at all made demons nervous (the book of Matthew has an account on that). However the main controversy is the pronunciation of the tetragrammatron (YHWH) which has been lost because in Hebrew tradition, one didn't take the name of God lightly. It was sacred. So the argument that usually follows is if no one has the actual pronunciation, is it necessary to use it or even acknowledge it. My personal response to that is, if it's in the Bible, it's probably important regardless.
Correction: It's never mentioned what happened to John's mother. She could have remarried, and so it could be John's stepfather being referred to.
Annabel Keeley
That is the only explanation that would keep the canon consistent, but out of universe, the writers almost certainly just forgot about that line.