Does Din know that Gideon dies? How does Luke know Vader’s alive in Empire Strikes Back? His ship was shot down in space…
You all keep saying plot hole, it’s not a plot hole.
The difference with ESB is that there was a time skip of 3 years in between ANH and that movie, by which point Luke would have has plenty of time to figure out Vader was alive. Mando doesn’t have any time in season 2 to figure that out offscreen, he’s on a mission the whole time. It is a plot hole.
Mando has plenty of time. It would have taken months for Nevarro to rebuild from the Imperial-occupied battlescape it was at the end of Season 1 to the thriving trade hub it is in Season 2. I expect Mando and Grogu had many dead-end adventures while seeking other Mandolorian covens: for this alternate movie timeline, we could assume one of those adventures is where he discovers Gideon’s survival.