Thanks for letting us know about this. I looked into the issue you described a bit further and, while it does appear to be a problem, the root cause of the problem lies on the eBay side of things. That is probably why you noticed several posts about this on eBay's discussion forums as well.
I can see that the options for "Subject" in the Custom Item Specifics section when category # 29223 is selected end with "Natural History" and it looks like there should be more options after that, but that is the same thing that happens when listing in this category directly through eBay's "Sell your Item" form.
We import that data directly from eBay so, unfortunately, there won't be able to do anything that we can do to correct the problem on our interface until eBay updates their system to provide the rest of the options that should appear in that menu.
It may be a good idea to contact eBay's customer support team to make sure they are aware of the issue and see if they can give you an idea when it will be resolved, although I suspect they must know about it since it is being discussed on their forums.
If you need any further assistance with your Auctiva account, please feel free to contact our customer support team by mousing over the "Help" tab within your account and selecting the "File Support Request" option.