nload & ioload plots sometimes drift sideways

With mosh-server 1.4.0 (Debian 13), sometimes nload starts scr

On the left is nload-over-ssh, but on the right is nload-over-mosh. nload-over-mosh starts drawing correctly, but eventually the top text area will slide sideways. This doesn't usually happen immediately, and only seems to happen when the plot contains nonzero vertical values.

ioload is based on the nload codebase, has same issue:

For both terminals,

$ export | grep TERM
declare -x COLORTERM="truecolor"
declare -x TERM="xterm-256color"

I wonder if this is something related to how nload/ioload draw with ncurses that mosh only exposes, or something where mosh is getting lost about how the plot moves.