This is a fairly minor bug. In the attached picture you can see that in the list of cards contained in the deck for LucasMcL, it says "-1 Death Carts". I had 0 death carts in my deck and this shouldn't be listed at all.
I think I know how this may have happened. I played an Overlord and played it as a Death Cart. My Overlord was then immediately trashed because I chose not to trash another action card. The game must have mistakenly decremented my total count of Death Carts from 0 to -1 in that moment.
The game was #15286219 on Tokyo.
I was playing in the chrome browser on Ubuntu 17.10.
Thanks for your bug report, LucasMcL!
This is indeed a problem, and your analysis agrees with mine. Unfortunately, this is more than a simple display bug, because it may affect victory points according to some landmarks (e.g. if Obelisk is counting Death Carts).
If you're curious, you can find a list of known card bugs here http://forum.shuffleit.nl/index.php?topic=1226
Your bug is already in there, on first position.
Apologies. I was thinking of it as a display bug, so I didn't think to check that list.
Thanks for the response!
No need to apologize. Almost all of the game logic works fine, and the remaining bugs are things that require special conditions that don't happen often, so its good that the community brings them up. That there are duplicates from time to time is not a problem.