Also had a strange occurrence in the training scenario.
Mild spoiler warning
Having ignored the suggested approach, for the training demo, (too much time in forests, too little time for MOUT) I found myself with ample time to clear the training complex. All my dismounts were rested or ready and only one squad had sustained a casualty, with good LOC to the platoon HQ. I broke down two squads into four fire teams to assault a row of four, two story, buildings in a terrace, via the back door, so as to take out a BTR 60. The fire teams (I'll call them 1,2,3, 4) all rushed into their respective buildings but two opened fire with AT4's (1 & 2), KO ing the BTR but shaking the furthest fire team (4) , who actually were on top of the BTR, but failed to spot it! The shaken fire team then split, with two soldiers remaining prone and two running out of the door, turning right, and then proceeded to run past the three other fire teams (3,2,1) and turning the corner so they could reverse the process and enter Building 4 from the front entrance!
Luckily, I'd ordered the assault at the start of the turn and was able to halt the miscreants before they exposed themselves. To get the team together, I had to issue a move order out the back door, for them to rejoin which they eventually did. I'd only ever seen this behaviour in CMSF1 when terrain oddities caused advancing units to be so fragmented.