During the scene where bellhop Yogi is asleep on a chair and Huckleberry Hound says, "we are giving away free picnic baskets" to wake him up, Huckleberry Hound's ears go from black, to blue, then back to black again.
During the tree trimming party song, Mrs Throckmorton's outfit switches from a long all-in-one dress to a skirt and blazer between many shots. Not to mention that the tree was already decorated when everyone first arrived to the lodge.
At the start of the cartoon during the trip to the lodge the bus full of male characters in the bus are all singing & they are all on key & singing well. Later on when they are practicing singing the Christmas carols for the party later they are all off key. The explanation given for the sudden poor performance is due to the lack of enough female voices, which did not seem to cause any problem during the earlier bus trip.
When Yogi is giving ski lessons, Boo Boo is seen in Augie Doggie's place, even though Boo Boo is back at the ski lodge.
During the opening musical number, Boo Boo's voice can be heard, even though he is absent from the scene. This is due to the fact that part of the audio was lifted from Casper's First Christmas (1979).
When the real Santa Claus shows up at the lodge's Christmas party his eyebrows' color go from white to black then back to white.
The name of the park is Jellystone. The first time the sign to the park is shown, it says "Yellystone."
Early in the cartoon Cindy says she cannot ski yet near the end of the movie she is shown skiing with the others while taking Yogi back to his cave.
Snively gets a hold of Yogi's hat & puts a frog under it as a prank. But the joke is never paid off later.
When Santa is at the lodge's party his hat changes color back & forth between scenes. Sometimes it is red & white then other times it is all red in color.
When Herman hears the announcement for the figure skating contest, he says to himself: 'I'll teach them city dudes to let Kermit the Hermit have a little peace," but in fact his name is Herman.
Twice when Auggie Doggie talks, it's Huckleberry Hound's voice.
Cindy runs to the lodge and begins singing without any knowledge of Christmas or it's songs.