Deliberate mistake: When the chickens are first shown, one of them is upside down.
Deliberate mistake: Many of the Rangers in the Legendary Battle could not be there since they were portrayed by the same person. All 3 Rockys, all 3 Adams, and both Jasons and Kimberlys were all present.
Deliberate mistake: When the dome is blacked out and blocking Chester's Mill from the sun, there should be no light at all in the forest, yet it's lit as if under a full moon. (01:10:40)
Deliberate mistake: The last season touched on Infinity War happening - this season jumps forwards a year, meaning that we should be one year into the "blip" (or snap), with half the universe missing. But The Team is all together, and the world/universe is utterly unaffected. Largely a byproduct of disagreement between the film and TV sides of Marvel, plus scheduling vagueness meaning they couldn't risk spoiling Endgame if they came back on the air before that was released. But considering the show is 100% part of the MCU, that's a pretty massive contradiction.
Deliberate mistake: Rick is talking to Joe in a maximum security facility through glass without a phone. It is impossible to hear through such glass. One would literally have to scream and still it would be difficult to hear. They should be on a two-way phone and those conversations are at times recorded, especially with high profile prisoners like murderers, mafiosi, terrorists. There's no way they would get away about discussing murder and revenge without an intercept. (00:14:00 - 00:15:00)