It's probably because of the ordering of the replacement.
It's looking for "be" and changing it to "b"
Then when it gets to looking for "be right back" it doesn't find it because it is now "b right back".
You need to make sure that the order of the results from the database are such that the data for "be right back" comes before "be"
Because you're ordering by 'keyword', "be" comes before "be right back".
It shouldn't matter what order they are returned from the database apart from this case you so can drop the "ORDER BY" but make sure in the database that "be right back" and its replacement are before "be" and its replacement