I have not brought the new DLC but I have downloaded the newest update. I loaded a previously existing save from before the update which worked perfectly yesterday. I found my sand mines have all disappeared and the build menu for them is strangely bugged and locked out. 
Hey guys, if you're using any mods, please remove them or wait for them to receive an update.
No matter if you're using mods or not, please verify the game files:
https://www.ubisoft.com/en-gb/help/connectivity-and-performance/article/verifying-game-files-in-ubisoft-connect-pc/000060529
Howdy @sicksock1 - thanks for coming back and confirming, we really appreciate that! I hope you'll be able to get the mod sorted 
devtrackers.gg