C-style and other code improvements unrelated to this issue.

malloc + bzero = calloc.

Missing a blank before the / operator.

Should be:
    case A_CSI: {
        int i;

        tem->tvs_curparam = 0;
        tem->tvs_paramval = 0;
        tem->tvs_gotparam = B_FALSE;
        /* clear the parameters */
        for (i = 0; i < TEM_MAXPARAMS; i++)
            tem->tvs_params[i] = -1;
        tem->tvs_state = A_STATE_CSI;
        break;
    }

Should be:
    if (isdigit(ch)) {

Missing a blank before the / operator.

Unnecessary extra whitespace.