Hi gbcs!
I wasn't able to reproduce this. I use Mudlet normally, but tried on a local telnet terminal too. You mentioned previously connecting via a web browser which could be a factor.
Based on your troubleshooting you could test something like:
modify.c
void show_string()
line 534
Code:
if (d->showstr_page + 1 >= d->showstr_count) {
/* Only append \tn when color is enabled to avoid ANSI leakage */
send_to_char(d->character, "%s%s", d->showstr_vector[d->showstr_page], COLOR_LEV(d->character) >= C_NRM ? "\tn" : "");
free(d->showstr_vector);
..etc
ps: you'll need to add this to the includes at the top of the file, around line 29
#include "screen.h"