In the rolling Johnny Karate credits the copyright year is shown as 2015, however, the episodes of season 7 are set in 2017.
When John Cena walks onto the Johnny Karate set, a small light-blond-haired boy wearing a red shirt is shown sitting between a girl wearing a blue shirt and a boy wearing a yellow shirt. A few seconds later, when the children are shown again, that child is missing and the space in the bench where he was sitting is empty.
When April introduces the Goliath Birdeater with a picture card, the picture is actually of an Ornamental tarantula (might be the Indian Ornamental), not a Goliath Birdeater.
When April dunks John Cena in the dunk take, his hands are out from behind his back when he is in the water. The handcuffs he was wearing disappeared.
During the Prof. Smart Brain segment, he starts to show how far Pawnee is from Washington, DC. The location of Pawnee on his map is placed somewhere on the west side of the Mississippi River, hundreds of miles away from its presumed location in southern Indiana.