What are some examples of revelations that occur very late in a show’s run that make you think, “Why is this the first we’re hearing of this?”

Submitted ⁨⁨1⁩ ⁨day⁩ ago⁩ by ⁨bOt@zerobytes.monster⁩ to ⁨television@zerobytes.monster⁩

https://www.reddit.com/r/television/comments/1vhdlpu/what_are_some_examples_of_revelations_that_occur/