i am trying - and somewhat failing but still trying - to not read too many spoilers. if you are speaking of the funeral scene...that is one that i do know about but its possible that she's back but because of the transformation still just appears as killer frost or retains her abilities but caitlain's personality is back in control? if otherwise, then no, i probably have not seen the spoiler you are referencing.

Producer and showrunner Andrew Kreisberg spoke about that possibility to EW recently, saying “We have a couple of recurring villains, one major recurring character [returning].”