I found the following omissions/errors while adding cards to inventory:

1. VI Edition - Plains: all four versions 331 to 334 show the same picture (331)
2. Coldsnap Theme Decks - Swamp: Only 375 is available, 376 and 377 are missing.
3. European Land Program - All five basic land types: Only one out of three versions available. -- FIXED
4. Duel Decks Elspeth VS Tezzeret - Plains #36 - If I use the split function, the new cards added are Time Spiral Plains #282. While normally the split cards are the same set/version of the original.
5. Invasion - Assault // Battery: when you open the inventory box two identical copies of the Invasion version are shown.
6. Sixth Edition - Island: all four versions showing the same picture.

I'll add any other similar findings to this post for ease of reference.

BTW The new functionality is awesome!