I have the same issue and one of my friends called me about it as well. I checked the sqlsrch_sql table and all looks fine. I also checked the .epj file for the report I was running and it seems to be calling the correct search function, which should be the case since the top search works, just the alternate ones.
I ran profiler against it and found that at least in my case, when it searched on the IM-ITEM one by Item Description it was trying to use the following command which as you can see is wrong:
exec sp_cursoropen @P1 output, N'Select ITMIDX_SQL.search_desc, IMITMIDX_SQL.item_no From ITMIDX_SQL
As you can see, it's dropping the leading IM from the table and description field. I can't say I know why but my friend is sending it to support.
Kevin Scheeler