Cannot edit/delete terms

A user has a subsite and she cannot delete or edit her tags/cats. She is one of the admins of that site. When she tries, she gets the following error:

“You need a higher level of permission.

Sorry, you are not allowed to edit this item.”

I’m a super admin on this WordPress multisite installation, and I get the same error. I’ve done some research, and I don’t know if I found a bug or not. Let me explain what I’ve done via an example.

I want to delete the category named China. I went to the dashboard, Posts->Categories, and clicked delete. Received the error above.

In the database:

select count(*) from wp_X_terms;
+----------+
| count(*) |
+----------+
|      234 |
+----------+
1 row in set (0.13 sec)

select * from wp_X_terms where name = 'china';
+---------+-------+-------+------------+
| term_id | name  | slug  | term_group |
+---------+-------+-------+------------+
|      39 | China | china |          0 |
+---------+-------+-------+------------+
1 row in set (0.13 sec)

select * from wp_X_term_taxonomy where term_id = 39;
+------------------+---------+----------+-------------+--------+-------+
| term_taxonomy_id | term_id | taxonomy | description | parent | count |
+------------------+---------+----------+-------------+--------+-------+
|              962 |      39 | category |             | 118398 |    10 |
|             1112 |      39 | post_tag |             |      0 |     8 |
+------------------+---------+----------+-------------+--------+-------+
2 rows in set (0.13 sec)

We noticed that if a term had more than one entry in the wp_X_term_taxonomy category, it could not be edited via the UI.

select t.name, tt.taxonomy, count(*) from wp_X_terms t inner join wp_X_term_taxonomy tt on t.term_id = tt.term_id group by tt.term_id having count(*) > 1;
+----------------+----------+----------+
| name           | taxonomy | count(*) |
+----------------+----------+----------+
| China          | category |        2 |
| Exercise       | category |        2 |
| Product Line   | category |        3 |
| Popular Topics | category |        2 |
+----------------+----------+----------+

(There were quite a few more results, but I truncated for brevity.)

Am I missing something, or is this a bug in WordPress?