Thought is a product of the brain’s conditioning."
True but all thoughts are not product of brain conditioning.
"the transformed brain will also produce thoughts like : “thought is limited”
True but this statement by a transformed brain is based on actuality of seeing the truth,not repeating what others have said as normally conditioned brain does.
Krishnaji’s statement:
“Repeating a truth is lie.”
what do you think K is pointing at here - let’s just assume that he is trying to tell us something important
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Lets imagine that I have adopted the concept that “thought is limited” because I’ve been listening and identifying with the teachings of K. And I repeat it in conversations I have with other people.
What might be the issue, or problem that K is pointing at?
Is the evil process fully mechanical?
When K used the word “thought” he was referring to psychological thought, the content of consciousness, the beliefs and conclusions that comprise the ego.
What I understood from Krishnaji saying that repeating the truth is lie is :
I have read Krishnaji saying that "mind is beyond brain. "
If I see the truth of it actually and not because Krishnaji said it and mention it in conversation with friends than it is not a lie. But I mention it without actually seeing the truth of it ,just repeating what Krishnaji has said, as though it is my own perception , then it is a lie.
Are we saying that some statement, taken to be true because of some authority, is corrupted?
If so, why is K pointing this out? What is important about this : that the authority of belief is problematic (in that it is corruption, it is a lie)?
For example : what kind of problems arise in everyday relationships because of the corruption of authority?
I want to say yes (unless Beelzebub has free will, is free from causes and conditions 
)
But if your question is related to anything, maybe an example would be helpful.
If an ‘authority’ says to me that it’s raining and I repeat it without verifying it, it’s a ‘lie’ because I don’t know if it’s raining or not. If I look out the window and see that it’s raining, then when I repeat the words of the authority ‘it’s raining’…it’s not a lie.
We had this conversation a while back if memory serves? I said we have a degree of free will, the ability to move around within our prison cell kind of thing. You disagree?
surprise surprise! and its not just us 
I have the ability to choose to want the thing I want - and I use the word “choose” quite wrongly 
Or I feel that I can decide what to do next - but what is “I” and in what way can we say that I have any agency in that choice?
If none of this seems to be addressing the question, sometimes people ask :
If we wind back time, and all things being equal, could you have chosen differently ?(but that doesn’t seem to provoke insight in most folk)
People (neurologists) also say : we can see that the brain sets in motion certain actions (eg. reaching for an object) before projecting the experience of “deciding” consciously to do the action. (this seems very insightful to me)
I have the ability to choose to want the thing I want - and I use the word “choose” quite wrongly
Why is the word choose wrong? Reword the first part to make it right.
Or I feel that I can decide what to do next - but what is “I” and in what way can we say that I have any agency in that choice?
The body-mind organism named Douglas has a degree of agency, oui? Forget about the elusive ‘I’ which may be a mirage, stay with the organism. Douglas, body-mind, has modest degree of ‘choice’ (or whatever word works better for you).
Staying with this Douglas body-mind thing, is it purely mechanical, a fleshbot? I’m not talking about what the Douglas bmt ‘might’ be (i.e. enlightened), but the Douglas that is reading these words. Is it a complex machine, c’est tout? (Not a leading question.)
It’s a lie because it’s a belief, and we’re all believers, so…
Do I choose my reaction to the words? Do I choose how I experience this instance?
Yes the ‘belief’ is that we exist as individuals. The belief is that I am the observer and that ‘out there’ is the observed. It is a fundamental belief, conditioning, reflex. It is a belief that I am going to die…belief coming from a conditioned brain, clouding the brain.
Maybe. Always ‘maybe’.
Your initial response is likely to be mostly automatic, conditioned, reflexive. But you may have more ‘choice’ in how to respond afterwards. In other words, you may have a fair amount of choice responding to your response, experiencing your experience. The question remains: Who-what is doing the responding and experiencing? 
So, the initial responses present themselves without any agency on my part. What about the experiences that present themselves after the first initial responses? Have I any more say in the matter? Come on this is all so obvious, whats going on?
Say I am presented with 2 or more choices (ie. the feeling that I have various particular choices arise in my consciousness) - do I decide which I prefer? (ie. have I any choice/agency in the matter? If I decide I prefer chocolate over vanilla, was that really a decision? )
If you really think there is an instance where there is some free will, please just make the case.
Rumplestiltskin
For example : what kind of problems arise in everyday relationships because of the corruption of authority?
the initial responses present themselves without any agency on my part
Likely.
What about the experiences that present themselves after the first initial responses? Have I any more say in the matter?
Well that’s the question! Let’s say your first response to a trigger (someone cuts you off driving) is blind rage. And your response to that is to understand the danger of your rage, the potential for violence. And your response to that is to look at the big picture: you, the other driver, traffic, your reflexive response to feeling cut off. And so on down the response stream. Are you saying all those responses are equally mechanical and automatic? Is there for you no room for higher and lower degrees of conditionedness in our responses to events in the world? Were Krishnamurti’s responses as robotic as Trump’s?
The choice was made when the belief/assumption that triggered the reaction was established. But the brain can review the reaction and choose to revise it or reject it.
Some (most?) brains are content to identify with their reactions, to stick-to-their-guns, as they say. More cautious, circumspect brains don’t trust their reactions but question them to see if they’re reasonable, appropriate, or just self-revealing.