When ncbo.c was updated from version 1.234 to 1.235, it ceased to append history. Between new line 574 and 575, you can see that the line below was removed and therefore the cmd_ln is not being appended.
if(HISTORY_APPEND) (void)nco_hst_att_cat(out_id,cmd_ln);
Thank you for reporting this. It is now fixed and will be in NCO 4.3.1 to be released real soon now.
cz