Hi,
Along with the test with statement cache off suggested by Bret, if the problem is reproduced, can you copy the exact result (just number of rows and/or message error) returned for each selects ?
I think this question should be discussed on the ASE for custom application forum, it will be helpful for others members from there 
http://scn.sap.com/community/ase-custom-applications
Regards,
Victoria.