Transcripts from wit.ai+Auphonic not recognized

Hello, I wanted to try out the transcript function after all. The setup of wit.ai with Auphonic worked fine, now vtt-files land on the server, which are also recognized as assets in Podlove. Now the problem: If I click on “Get from asset” in the transcript field of the publisher, nothing happens. The same with manual import. Any idea what could be the reason for this? Thanks!!

Have you saved the episode before doing this? Otherwise, please post urls to the files.