As explained verbally (but just for the record, so other people know we take these matters seriously), the toolkit that Wilco uses to create billboard and mission-map objects in game has recently been updated, and now has a problem placing billboard and other objects correctly in the game-world. We are currently progressing this with the toolkit's author and hope to find a solution soon. Alas, we are utterly in his hands in terms of a date for a fix (but are looking at other strategies in the meantime).
However, if anyone reading this has kept a pukka installer for MCC Sandbox VERSION 3 (note, not version 4), please let us know (don't bother Googling for it - all the links out there on the net are for version 4, sadly, even if they say version 3. Ultimately, we're hoping that someone reading this has kept their original installer file for v3 and can physically pass us the file. The original author has deleted all his copies, and Wilco isn't as OCD as me, and didn't keep a spare!)
Side note to Price: thanks for looking. And if you give me the info (via PM) about your squad.xml, I am still aware I promised I will fix that.