Full-text search and guest upload (upload only): error message appears

Hello, I have the following problem under NC 15.04. When I activate the full-text search (with all modules of elasticsearch), an error message is always displayed for guest upload (upload only) - Could not upload “test.pdf” -. The file itself was successfully uploaded. If I deactivate the full text search again, no error message appears and everything runs normally. That’s already been the case with the NV 15. And is still the same with the current 15.04. I think there is a mistake here. Thank you.

[core] Error: TypeError: Argument 1 passed to OCA\Files_FullTextSearch\Service\FilesService::getFileFromPath() must be of the type string, null given, called in /var/www/html/apps/files_fulltextsearch/lib/Events/FilesEvents.php on line 135 at <>

[core] Error: OCP\Files\NotPermittedException: at <>

Can anybody confirm this? Thank you.