This is not my crazy idea, that what i heard, and i repeat i don’t believe in that any bit.
Well that’s what i see in my debug.log NOT in harvester.log, don’t you have these warnings?
So i’m fine? 
Well, how could i reduce this time or ideally get rid of the whole set of such warnings?
No, just WARNING
Warnings are just that. There are many warnngs and you only need to be concerned about them if they indicate a larger problem. This WARNING does not.
Most of the time you only need to stress about ERROR messages. You are in good shape.
You might just stress yourself out, but you do not see the important messages unless you set your log to INFO. ERROR messages are seen when the log is in INFO mode. These are the important messages, but even many ERRORs are not a real problem.
This is one of the reasons to install farmr. It sets your log to info and monitors the results. After under 24hrs you will see if your farm is having any problems.
farmr would have ignored this warning as it is not part of the farming/harvesting process and not causing any problems to it.
Alright! Champaign to everyone. On me !! 
I’m sorry, I manually searched several of my past log files in notepad, and I have no “WARNING: Block validation time:” entries at all. Same goes for “WARNING: Sending data failed:” entries.
You do not get the WARNING if your validation time is under one (two?) second(s).
but that is interesting … you should have that now and then, lolz!
“Interesting” … “you should have” ? I though WARNINGs were not so good, something to be aware could become problems, even ERRORs at some point. Wouldn’t a WARNING free log be best??
This warning appears after you have dropped a peer and the validation took longer as a result.
The fact that you do not get the warning says to me (maybe incorrectly) that your validations are under two seconds even after dropping a peer.
This would indicate your system performs extremely well.
Most warnings just indicate that something happened a bit slowly and are not to be worried about.