Like many of the users here, I am having issues with the flashcard decks:
Issues: Random word replacements, incorrect vocabulary lists from lessons, replacement of "mastered" words with new unstudied random words for incorrect learning percentages.
Observations: It appears that Jpod101 is overhauling all of the flashcards by changing existing ones. The newer flashcards have an image and at least 4 pretty good example sentences. The older flash cards do NOT have an image, and only have one or two example sentences, many of which are something useless like, "わたしは(vocab word)です。" The even older cards appear to have definitions separated by / instead of , but I'm not sure. The flashcard database seems huge, so it will take some time to phase out the old cards and complete the newer card format. I just wish there was a way it could be done without affecting our existing flashcard decks. Maybe complete them off the website, then shutdown the flashcards a day or two to install the new cards? I think everyone would be ok with this. It's extremely annoying to go through a deck and find that you have 100% learned a word you've never seen before.
Workarounds: Big decks are more likely to be corrupted. I previously would make decks of an entire lesson season, but that only makes the corruption more difficult to see. I now use smaller decks, one for each lesson, and delete words as I memorize them, and then combine smaller decks together to make bigger decks. It's a pain but it's been a lot easier to keep track of what words are being changed or deleted.
I hope tech support and other users find this post useful, I also welcome any other tips or flashcard workarounds.
-Dan