Bex transport request problem

Hello gurus,

we opened BEX request for changing the existing reports. when after transporting the query into quality it has ended with return code 8.

After checking the request , we concluded that some of the Bex query elements like selections were not transported.

We do not understand the reason .

is it possible that Bex request sometimes not able to collect the query elements .

please can somebody give me a clue.

Regards,

Veera