An example of these abnormal values (i added the "|cat -v" at the end of the command to convert the non-ascii chars to standardized notations to avoid the loss/modification of those while copy/pasting to JIRA) :
Insert queries in the example has been stripped for security reason but all looks the same but not ran on the same base and table ; these queries are all almost the same.
This does not seems to happen on the other server under MySQL 5.5.30 having the same tables/structures and applications executing the same kind of queries.
I havent found so far anything out of the ordinary on the app executing the queries (it does other queries than these INSERTS using the same function without encountering the same bug.
ps: it seems that the STATE value on INFORMATION_SCHEMA.PROCESSLIST is correct and is "Repair with 3 threads" for the problematic recuring INSERT queries so the bug is only on the output of the SHOW PROCESSLIST command.