Thank you all for your replies. I made another attempt at inserting the alternate card which mirrors the original and unfortunately the Aura froze, book covers turned to blanks and no processing was evident, i.e., black processing screen. Perhaps the number of books is the reason (about 90). @davidfor - I suspect you are right that there is a timestamp or some other file created that differentiates the two cards even though the content is identical.
I am perplexed as to why something so straightforward is not functioning as expected. I think I will have to resort to RZetlin's method and start with a blank card and add the books back via Calibre
