Below are links to details:

CentralAuth shows that User:ZH979433@zhwiki has 0 edits.
[[meta:Special:CentralAuth/ZH979433]]

but tools didn't pick up the local account.
http://toolserver.org/~quentinv57/tools/sulinfo.php?username=ZH979433
Due to the replag, a few hours ago the sulinfo tool still showed that ZH979433@zhwiki had 5000 edits.

Now we have an unmerged User:Shujenchang@zhwiki. All his edits seem to be attributed under this username, however [[w:zh:Special:Contributions/ZH979433]] and [[w:zh:Special:Contributions/Shujenchang]] are showing the exact same thing.

It looks like:

user_name in user table has been reverted.

• 1. row ******* user_id: 979433 user_name: Shujenchang

every _user_text in other tables are not affected.

• 1. row ******* rev_id: 25406107 rev_user: 979433 rev_user_text: ZH979433

Now [[w:zh:Special:Contributions/Shujenchang]] is querying revisions for a logged-in user, revisions are listed based on rev_user. [[w:zh:Special:Contributions/ZH979433]] is querying revs for anon users, and revs are listed by rev_user_text...

I redid the renaming.

A similar situation:

mysql> select * from revision where rev_id=24215946;

+----------+----------+---------------+

+----------+----------+---------------+

+----------+----------+---------------+

However this revision belongs to Kontos, who was renamed to Sanyi4 in Feburary,

https://zh.wikipedia.org/w/index.php?title=Special%3A%E6%97%A5%E5%BF%97&type=renameuser&user=Bencmq&page=User%3AKontos&year=&month=-1&tagfilter=&uselang=en

Yet his rename is also somehow reverted