I can't say what I'm about to write is 100% true, but I see this almost every day on some of my sites and clients.
It mostly happens with pages that aren't old enough that don't have a large number of backlinks yet.
I will add 2 pictures, in the first example with less search we have more bounce while in the second picture you have less bounce and a more "stable ranking" after indexing some of the backlinks in September, still, it bounces a lot but not as the other pages.
Example #1 : Keyword - 1.000 searches
Example # 2 : Keyword - 10.000 searches
In any case, both sites are on a very small budget and of course, the result is unpredictable in such cases.
There are too many factors involved in the game for anyone to guarantee any results today, whoever says that is lying.
EDIT: I should add that, whoever reads this and has this kind of problem, results will come in time, you just have to wait for it of course if you do it the right way.
It literally can take 6 months to see any movement, if you are on a small budget or you do it on your own way without investing a single dollar, it's gonna take some time...