[Original]
Player has hard-defined weapon on start of the mission but he has plenty of options to switch weapon in previous mission from corpses (his commanders MX/GL/optics, marksmen rifle / MK200 machinegun / default green army rifle).
I recognized this as I had MX/GL when I enter Maxwell but on the beginning of the next mission although it is supposed to take place immediately after the briefing, I had MX without any addition in my hand. Therefore I presume the weapon in hand is not related to the previous mission even when it should be.