Chapter XIV, Section 2 of the rules:

CIVIL DISORDER REMOVALS. If a country in civil disorder has to remove units, because it has lost supply centers, the unit farthest from home (most distant from the nearest home supply center as computed by the shortest available route, including convoys) is removed first, the fleet before the army. If more units are equally eligable fro removal than should be removed, priority is established by the names of the space in which they are located, the earliest in alphabetical order coming off first.

I've had the same doubt of nekudza.
Seeing the unit destroyed by Hungary in this game gameID=19363, I suppose official rules are not applied (or there is some bug)

No, the rules are applied correctly. Boh is not a Hungarian *home* SC. The unit in Ser is closer to Sze, which is a home SC for Hungary, than Boh was so the former unit is kept while the latter is destroyed.

This is a good example of a necessary improvement to the overall WebDip coding in case anyone here has a platform to share such suggestions.

Do you mean that you want to change the rules or that the code implements the rules incorrectly?

Presently the adjudication of CD/NMR disbands does not follow this rule. My suggestion is that the Web Dip coding be written to match the rules of the game that you posted above.

Do you know what the current algorithm is for CD disbands?

Here is the dev-forum for folks interested in working on improving the source code:

http://forum.webdiplomacy.net/index.php

(no idea on what the current algorithm is - sorry)

I agree the default should certainly be the standard games rules, but if someone wanted to substitute different rules, then they should be stated from the start. Then anything can go, but aside from that, the standard rules should apply.
(myself, I would not mind changing to make any supply center held more important than a non supply center held closer to home.
EX. if you are Germany and need to disband (because you just got beat by USA soccer perhaps?) if it's between say an army in Bohemia or an army in Budapest, the standard rules would remove Budapest, I do not mind changing to instead remove Bohemia, but that's just me and that should not be the default, if such a change were made it would have to be clear and spelled out before the game started, the default should be the standard rules!!!

it seems it's obvious that it's not obvious =(