As `kovidgoyal` says:
> Add the following to your .vimrc
" vim hardcodes background color erase even if the terminfo file does
" not contain bce (not to mention that libvte based terminals
" incorrectly contain bce in their terminfo files). This causes
" incorrect background rendering when using a color theme with a
" background color.
let &t_ut=''
source- <
Hope it helps!