Known problem although the fact that you are using Firefox, not Chrome, might be the problem.
Mess with the Bill, you get the scorn!
Hello!
After the day change, one of the units on the map is reported to be under my command. However, he cannot be moved and his contents remain a mystery.
When clicking on the refresh button (twin arrow on the bottom-right corner), the unit does not go away nor disappear from the map.
If an attempt is made to move the unit, the game reports the server state differs from client.
Closing the tab on the web browser and reopening the game does not resolve it. I believe that he does not exist and it's an issue.
(Please note that the bookmarks and tabs have been removed for privacy. Further information can be furnished upon request from a Moderator or member of Bytro Labs.)
Please check out the image below:

Hope this helps!
Known problem although the fact that you are using Firefox, not Chrome, might be the problem.
As this issue is well documented and in other threads I am closing thisone.