A short mini-video for better understanding:
http://i.imgur.com/Uz3r3b3.gifv

It always happens when auto-complete should kick in.

Logs:

366164-2017-01-17 13:19:31.004 sogod[10752] <MySQL4Channel[0x0x7f5b91b37f10] connection=0x0x7f5b91a6b720> SQL: SELECT * FROM sogo_dynamic_table WHERE (LOWER(c_cn) LIKE '%isa%' OR LOWER(mail) LIKE '%isa%' OR LOWER(aliases) LIKE '%isa%' OR LOWER(ad_alias) LIKE '%isa%' OR LOWER(senderacl) LIKE '%isa%') AND ((domain = 'domain1.de') OR (domain = 'domain2.de'));
366165-2017-01-17 13:19:31.004 sogod[10752] <MySQL4Channel[0x0x7f5b91b37f10] connection=0x0x7f5b91a6b720> query has results, entering fetch-mode.
366166:EXCEPTION: <NSException: 0x7f5b91c45ec0> NAME:NSInvalidArgumentException REASON:Number of objects does not match the number of keys. INFO:(null)
366167-Jan 17 13:19:31 sogod [10694]: <0x0x7f5b91737ef0[WOWatchDogChild]> child 10752 exited
366168-Jan 17 13:19:31 sogod [10694]: <0x0x7f5b91737ef0[WOWatchDogChild]> (terminated due to signal 6)
366169-Jan 17 13:19:31 sogod [10694]: <0x0x7f5b90f1e3f0[WOWatchDog]> child spawned with pid 11873
366170-2017-01-17 13:19:31.028 sogod[11873] MySQL4 connection established 0x0x7f5b917a6e00

The query returns data just fine in MySQL.