When Sydney's car won't start, Mac looks under the hood for a couple of minutes (without trying to start the car) and says "It looks like a bad fuel pump." The fuel pump is not under the hood anymore, but back inside the gas tank.
Mac invites Sydney to dinner. After having dinner in a lovely darkened restaurant, they walk out into afternoon sunlight. The week before Christmas.
Rayanne tells her age as being 8. Mack is a 4th grade teacher, meaning his students are probably around the age of ten. When Mack drops off the winter reading list Bea mentions that Rayanne is the same age as his kids. That is impossible.
When Sidney is reading the book jacket about Mac's bio, there is a typo in the word "ourdoorsman". The 'r' should be a 't'.
There is a scene where Mac and Sydney are sitting on the couch. When Mac goes to place his right arm around Sydney's head you can see a gaping hole in Mac's sweater in his armpit. It happens quickly but the hole in the armpit of his sweater is quite evident.
Sydney tells Mac she is going into the city (New York) and will be back for the carol sing that evening. Not a realistic or believable plot sequence to travel from a small NC town with no major airport to NY city, meet with a corporate board of directors, and be back in NC in the early evening.