Thumbnails work for RAW images, but clicking starts a download instead of expanding the preview?

I have a lot of raw images in my cloud (e.g. .arw and .rw2). imagemagick clearly generates previews for them, since I can see the thumbnails in the Nextcloud web interface. However, when I click a jpeg or similar file, a larger version of the preview opens. When I click an arw file, it starts a download instead.

How can I make clicking an arw file open the big preview instead of downloading it?


Have the same problem since Nextcloud 28. Did you find any solution?