Using the Army Casualty lists on FindMyPast I have found two records for one man. The numeric code on one (L1215/..) clearly links that record to an updated list. However on the updated list there is a code 582 which does not link back to the original list and it does not appear to link to a third list as list 582 is dated more than a year before the death in question. What else could it be? I've noticed a number of other entries with 581, 580 codes.
I've also seen the discussion at
https://www.rootschat.com/forum/index.php?topic=780309.msg6345495#msg6345495
