Back from vacation.
You're right, we need to update to the latest libraw libraries. I tried downloading the "binaries" for various OSes, but there are no precompiled files (".dylib" on Mac) available, and when compiling I end up in a never ending list of errors due to missing 3:rd party build tools. I'll eventually get there, but if anyone can manage delivering precompiled ".dll", ".so" and ".dylib" files for Windows, Mac and Linux, it will save me a lot of time.
Can you pass the images in this thread to the libraw developers for inspection?
Sorry, but I'm not the right person to tackle this. I know nothing about RAW images, and nothing about LibRaw. I'm pretty sure that they would immediately try to engage me in a conversation in which I wouldn't have the slightest idea what they were talking about, or in which they would want to know things like how my iOS device is configured (a challenge, since I don't own one), or how I'm compiling this into my application (another challenge, since I'm not doing that, and wouldn't know how to).
I'm going to have to leave this to someone else. Perhaps the OP would like to venture into it?
I haven't forgotten about this one, and I still have a folder with a few of your "problem" DNG files.
Using the latest jAlbum beta, v. 29b15, things have changed. Still not great, but usable for your purposes. I suspect that's how it will be in the final jAlbum 29 release, coming soon to a theater near you.
Here's what happens.... If you add one of those DNG's to a project, there is a console error message, and you get a "red X" thumbnail, but nothing else goes wrong. Now, if you try to build the album at that point, it will crash. However, you can use an ignore pattern to avoid having the core try to process those files. Under Settings > Advanced > General > Ignore pattern:
That's telling jAlbum to ignore files whose names start with a "dot," and also to ignore any file that ends with ".DNG". Once the album is built, the "bad" thumbnails vanish from the Explore view (ETA: on the Mac, is seems to need a "save, close, reopen" before the bad thumbnail goes away).
So, less than perfect, but probably good enough to let you continue your current workflow.