As you say it woks good in Dev,
1) try to create a new transport, Include the RFC from the imported objects as well in the Transport request and make a fresh transport.
Check both PI & ABAP, RFC in quality match with the fields.
2) Not sure if you had any cache problems earlier during the import,as you say manually you are trying to perform changes in QA which is not a good idea, this results sometimes with inconsistency with the mappings. When you try to next import from DEV to QA then you might sometimes have conflicts.
Try to check if you have any conflicts in the QA system. (next to the change list tab) there will be conflict tab located sometimes.
3) If the above 2 are not helping try to create a new service interface name for Outbound to include the RFC request and perform OM using this new service interface.
All the best.
Cheers