This problem was originaly mentioned as an aside in Issue 18594
to which the responder requested a separate issue be opened.

So, with refence to 18594, here's the equivlent query using BETWEEN.
SELECT `POSTEDDATE`, `PAYEE`, `BANKTRACE`, `TRANDATE`, `VENDTRACE`, `AMOUNT`, 
`MEMO` FROM `CHECKS` `CHECKS`
WHERE `POSTEDDATE` BETWEEN {D '2003-07-01'} AND {D '2003-07-31'}
ORDER BY `POSTEDDATE` ASC

This gives an error box saying
"parse error, expecting 'BETWEEN' or 'IN' or 'SQL_TOKEN_LIKE'"

This query does run correctly if "Run SQL command directly" is used.