In Issue #00004139 we tried to solve the problem - but didn't succeed.
The current solution is OK if we have only one attachment and does not work if we have more then one.
If you hit two (or more) attachments contained in the same content you will see the last attachment twice instead of two separate attachments.
We now hopefully have a better solution:
We now generate a "random qualifier" for this WGDocuments so that each of them has ist own independent session context (carrying the search details infos).
Note that the problem only appears if the query is either processed in an indirect manner, like reading results to a list and then putting them out, or if you have a pagesize in <tml:foreach> with "filllastpage" being true (which is the default). So in case of a <tml:foreach> a workaround is to set filllastpage="false".