I have had the bad experience of loss of my companions equipment. Both ED-E and my Mexican Ghoul companion loss gear that I gave them. I had set them to wait in the Lucky 38 and when I cam back ED-E had lost a modded Fat Man, 6 C-4 charges and a detonator, he did retain the 20 weapons repair kits. The other companion lost a Trail Carbine I gave him to use, but the 1400 rounds of ammo were still there. I have all the DLC's installed and some player mod's like World of Pain and a armor repair kit mod. But I never lost any gear from my companions until I installed the last 2 DLC, Honest Heats and Old World Blues. FYI.