Thank you.
I've acepted different criteria in my solution that's why it always fails in at leat one test case.

Will retake this kata later on.

5 is not a peak, the next value is greater.

shouldn't potential a peak value be greater than last and first el in order to actually be a peak?

No, being a peak (or local maxima) depends on the surrounding values.

ok. Thank you
But what about 5 than?

Also, if last and first elt-s should not be considered as peaks which is clear, shouldn't potential a peak value be greater than last and first el in order to actually be a peak?

Sorry for the late reply, your code is wrong, it's giving false positives on things that aren't plateaus. Print the input and you'll see it.

The first and last elements of the array will not be considered as peaks (in the context of a mathematical function, we don't know what is after and before and therefore, we don't know if it is a peak or not).

3 is the only peak there. Use Question label next time.