ncurses - can't print multiple times the same character with addstr and/or addch

I have been playing around with ncurses in C a bit, and have been trying to get this little piece of code working correctly for an hour now.

I try to print a 3x3 field of the form: (just in 3x3 instead of 2x2)

00000
0 0 0
00000
0 0 0
00000

And I think my code is working correctly, no warnings or errors are appearing, but instead of 00000 it just displays 0.
I.e. when I change my code to display abc it does display it.

Code:

#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <ncurses.h>

void drawfield(uint16_t size, char c);
void quit();

int main(int argv, char **argc) {
    //read in the man page, that these settings should be good
    initscr();
    cbreak();
    noecho();
    curs_set(0);
    atexit(quit);

    drawfield(20, 'b');
    refresh();

    getch();
    return 0;
}

void drawfield(uint16_t size, char c) {
    //Preparing strings
    char *line = (char *)malloc(sizeof(char) * (size + 1));
    char *rest = (char *)malloc(sizeof(char) * (size + 1));

    // line should be of format "ccccccccc", while rest should be "c   c   c"
    for (int i=0; i<size; i++) {
        // if i use c+i instead of c it seems to work fine
        *(line+i) = c;
        *(rest+i) = (i % (size/3))?' ':c;
    }
    line[size] = '\0';
    rest[size] = '\0';

    // debug output, strings seem to be correct
    printf("line: %s \n rest: %s \n", line, rest);
    sleep(3);

    //Drawing part
    //Should be drawing a 3x3 field
    for (int i=0; i<size; i++) {
        if (i % (size/3) == 0) {
            mvaddstr(i, 0, line);
        } else {
            mvaddstr(i, 0, rest);
        }
    }
}   
void quit() {
    endwin();
}

Output: (the same character method):

b
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
b
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
b
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
b
b     b     b     b 

(changing the character)

bcdefghijklmnopqrstu
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
bcdefghijklmnopqrstu
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
bcdefghijklmnopqrstu
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
b     b     b     b
bcdefghijklmnopqrstu
b     b     b     b 

I also directly tried using the addch method instead of addstr, but it doesn't seem to make any difference.

If you know why this happens and/or how to work around it, I would really like to know! Thanks in advance.

EDIT:
I'm using ArcoLinux as my distro and gcc as the compiler using the -lncurses flag

EDIT 2:
The problem was that I was using urxvt, but had set the TERM variable to xterm-256color instead of rxvt-256color. Changing this via my .Xresources files termName entry fixed it.