Photos export creates very small images (for panos) only

Photos recently started to create very small, thumbnail sizes images when exporting to filesystem as large size.

To provide an example, I have one image, a pano created on iPhone, with 11438x3880 pixel and 10.5MB of size.

But when exporting it, regardless of selecting medium or large size, I'm getting images of 190x64 px and 7KB of size only, thumbnails pretty much. Usually this would create an image of around 1280px width and around 150KB in size when exported.

I observe this issue with some images only, another image next to it in the library exports fine into various target sizes. Also can I always export the original size without problem.

My suspicion is that the problem might in particular be with panoramic images, as I can reproduced the issue there on a regular basis. But have not yet found an indication what the source of the issue might be.

Anyone has seen this as well?