Squad changed weapon in mid-turn oddity

[c3k]

Gents,

Watching through a replay I noticed something new. My 6 man US squad had a single M249 (plus the various M4's). With just a few seconds left in the turn a flicker on the Team Info Panel (the green or yellow weapon icons) caught my attention. The M249 gunner, in green, changed to an M4A1, in green. They were in the midst of firing on an enemy unit when this happened.

Has anyone else seen this?

Is this supposed to represent a weapon breakdown? If so, is it normal for M249 gunners to also carry an M4?

If it's not a weapon breakdown, what was it?

Savegame available.

Thanks,

Ken