eshell-scroll-show-maximum-output

eshell-scroll-show-maximum-output is a variable defined in `esh-mode.el'.
Its value is

t

Documentation:
Controls how interpreter output causes window to scroll.
If non-nil, then show the maximum output when the window is scrolled.

See variable `eshell-scroll-to-bottom-on-output' and function
`eshell-postoutput-scroll-to-bottom'.

You can customize this variable.