Multifiling works now and then when concurrent

My integration testcase works perfectly when running standalone but I'm have trouble when running 3 instances of it at the same time.

I use multifiling to store a document under 2 folders like this.

Folder folder = (Folder) cmisSession.getObject(folder1ObjectId);
Document  document = folder.createDocument(properties, contentStream, VersioningState.NONE);
document.addToFolder(cmisSession.createObjectId(folder2ObjectId), true);

Yet when I do a query and use getParents() on the resulting document I sometimes only get folder1.