why are my cylinders stretched if i use this geometry setup i have this very simple geometry nodes setup:

result is:

my cylinders are stretched. I would have expected that the cylinder form is the same, but the just got bigger distances. Why is that?
blend file:
This is happening because you're doing the operation (in this case add on x-positions) after instancing the cylinder. So, you're modifying the x-position of each vertex of the instanced cylinder instead of the x-position of the points that you used for instancing.
Thus, you have to first modify the x-position points then use them for instancing of cylinders,