As multiple questions have answered, the Jedi by the end of the war, learnt that Tyranus was Dooku. As Obi Wan says,

"Tyranus? You are the man called Tyranus?"

Now, during Attack of the Clones, Jango Fett says to Obi Wan:

I was recruited by a man called Tyranus on one of the moons of Bogden.

As correctly confirmed later on, the Jedi in a council meeting acknowledge that their army was funded by their opponent and that this was the plan of the Sith Lord. Their decision to not make this publicly known is understandable, as shown by the quotes below (also found in another question).

Yoda: "Know now we do, that guide the creation of the clones from the beginning, Dooku did."

Mace Windu: "Hmm, our enemy created an army for us."

Ki Adi Mundi: "If this was known, public confidence in the war effort, the Jedi, and the Republic would vanish. There would be mass chaos."

Yoda: "Cover up this discovery we must. No one, not even the Chancellor, may know. Valiant men the clones have proven to be. Saved my life, and yours they have many times. Believe in them, we must. Win this war swiftly we must, before our enemy's designs reach completion, whatever they may be."

Mace Windu: "Are you sure we are taking the right path?"

Yoda: "Hmm, the right path... no. The only path, yes. Designed by the Dark Lord of the Sith, this web is. For now, play his game, we must.

All up to this point have been explained in other questions, I'm aware of this.

What does not make any sense to me is their decisions to not communicate with the clone makers in Kamino. Only a few episodes earlier, we saw Nala Se communicate with Tyranus. Only a few episodes earlier, a clone killed a Jedi and Fives tried to warn the Jedi. Not informing the public is logical, however not checking on the clones and their inhibitor chips doesn't make any sense.

Additionally, why would they not communicate with the Kamino-ans? I mean they knew the truth from the beginning, there wouldn't be any damage if they asked, what requests had Tyranus made to you and playing along with the responses, the same thing Obi Wan did in Attack of the Clones. That won't reveal to them he was Dooku, but will lead them to learning about Order 66, especially considering the recent events with Tup and Fives.

I mean the so valiant and trustworthy clones had just killed a Jedi and that combined with the fact they're hired by Dooku and the (granted, even if it was disillusioned) warning of Fives about the inhibitor chip, gives out Order 66 immediately without even harmlessly asking the Kamino-ans.

How can such an oversight be even explained?

closed as primarily opinion-based by Buzz, Bellatrix, Ward, Edlothiad, Valorum Jun 3 '18 at 8:21

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

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    Question should be edited to "why Jedi didn't contact Kaminoan cloners" and then reopened , because it is interesting . – rs.29 Jun 3 '18 at 9:38
  • Well define oversight, and whose? The Jedi? That's intended. The Kaminoan cloners are aligned with the Sith, Dooku is aligned with the Sith and the Jedi become aware of this and their interaction together and nearly uncover the whole plot. If it went any further there wouldn't be a Revenge of the Sith. The prequels would have had a Scooby Doo ending! :) – Jacob Andrew Hollander Jun 3 '18 at 12:20
  • @Jacob Andrew Hollander True, for continuity it shouldn't be revealed. The Kaminoans though weren't aligned with the Sith but with whoever paid them. As Tyranus says to Nala Se, "This order is to stop a Rogue Jedi. Only master Sifo Dyas knew" to justify the contrast with the Council. Then Nala Se says "Strange these Jedi" suggesting she thought Tyranus was a Jedi. Kaminoans were fooled too, which strengthens why the Jedi should have asked to confirm with Kaminoans if the chip and order 66 mentioned by Fives were real. I feel like the show created a plothole when they revealed Tyranus as Dooku. – isklikas Jun 3 '18 at 13:52
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    This question is definitely not a primarily opinion based one. If there is no further explanation in the sources a simple "we don't know" would be a perfectly acceptable answer. – C.Koca Jun 3 '18 at 14:44
  • Hmmm, okay. I had forgotten exactly how that played out and I gotta say that's a little too convenient , I mean how could the people who are making the clones not be aware of everything about them? That's the plothole to me, it just simply makes no sense. How the episode should have played out is that the Kaminoans were in on it but they managed not to have their cover blown. – Jacob Andrew Hollander Jun 3 '18 at 17:39