I updated your branch and tried with it. The same problem occurs:
1/ Set the interface to English (in French it is the same problem)
1/ "Products": choosing one product (eg. the first : 10039)
2/ "Reference data": choosing "Raw material"
3/ Click on "Search"
4/ The preview is empty, it's ok.
5/ Click on "Download the file".
6/ The page fails with an error 500 : "Unable to find the choice Raw material". It's URL is http://localhost/soerepro-merge/?r=soeretypo/extraction/metadata_pros_infos&download
I updated your branch and tried with it. The same problem occurs:
1/ Set the interface to English (in French it is the same problem) localhost/ soerepro- merge/? r=soeretypo/ extraction/ metadata_ pros_infos& download
1/ "Products": choosing one product (eg. the first : 10039)
2/ "Reference data": choosing "Raw material"
3/ Click on "Search"
4/ The preview is empty, it's ok.
5/ Click on "Download the file".
6/ The page fails with an error 500 : "Unable to find the choice Raw material". It's URL is http://
You can find the debug trace as an attachment.