Guba and his sidekick, Angelina, are invisible!

This seems to be happening to players with OFP: Resistance version 1.75, who are going back and player the 1985 Cold War Crisis campaign.

According to OFP player, Ralph Wiggum ("here's looking at glue, kid!"), this is caused by OFP: Resistance's changes in rendering objects inside of buildings. In other words, it's a bug. This problem still exists as of OFP: Resistance version 1.91. Hopefully, the good folks at BIS are well aware of it and will incorporate a fix in an upcoming upgrade patch.