Yoda's influence over the first two trilogies in the Star Wars universe is massive. He mentored both Luke and Anakin Skywalker, and helped them accomplish extraordinary things. However, the prequel-era Jedi Council helmed by Yoda seemed to be more concerned with politics than the finer points of the Force, and a new theory proposes a grim reality to explain why.
Reddit user TheMediocreCritic argues that Yoda and the Jedi Council had already lost connection with the Force by the time of Star Wars: The Phantom Menace. Thanks to Luke's conversations with Rey in The Last Jedi, we know that one's connection to the Force isn't a permanent thing. It fluctuates depending on events. If Luke was able to willingly disconnect from the Force, it's also possible that the Jedi Council's ability to tune into the Force had diminished without them fully realizing what was going on, until it was too late.
There's a surprising amount of evidence to support this interpretation of Yoda's exile and explain the Jedi's continued bungling amid Palpatine's rise to power. How could they not sense Palpatine being Sith? Why weren't they able to stave off Anakin's Dark-side inclinations?
The Jedi Council was a bureaucratic cult in many respects. Perhaps as they got caught up in policies and diplomatic issues, their connection with the Force weakened.
The first instinct to rebut this theory is to bring up the epic Force powers Yoda exhibits. He moves an entire column in Attack of the Clones, after all. Someone who's lost their Force connection can't do that. The theorist has a pretty compelling explanation for why all this "moving rocks" stuff still works, though. In instances where the use of the Force would assist the Chosen One, Anakin, the Force will connect. That's why Yoda was able to absorb Force lightning, but Mace Windu wasn't able to withstand Palpatine's fury later.
Obi-Wan, however, still maintains his connection and has no idea about everyone else's deception. This, at least, allows him to be a good master for Anakin to learn the ways of the Force. With a theory like this, it's comforting to know there was at least one good role model in Anakin's life, even if it's only to balance the other mentor he has: Darth Sidious.
This explains why Yoda exiles himself to Dagobah. It's out of his own personal guilt that he couldn't sense the coup and Order 66 coming. He blames himself for the Empire's rise, and while that's not entirely true, the Council's deception would not be something to be proud of.
The Inverse Analysis – There's a lot to digest here. Deception of this level would surely be uncovered at some point, but it absolutely explains some of the Jedi Councils plot-dependent ignorance of certain events and character traits. That's the issue with giving some characters omniscience: it's really difficult to portray them getting fooled.