Yeah, you should give it to them in the GECK, then they'll definitely have it.
Their inventory probably resets if they're more insignificant characters who normally wouldn't equip other items.
It's much faster and easier to do it in the GECK too, you can just drag and drop it in their inventory and that's it, no command's required.
_________________
A secret message to the chosen ones:- Spoiler:
011010000111010001110100011100000111001100111010001011110010111101110111011101110111011100101
110011110010110111101110101011101000111010101100010011001010010111001100011011011110110110100
101111011101110110000101110100011000110110100000111111011101100011110101100100010100010111011
10011010001110111001110010101011101100111010110000110001101010001
by 
Calendar
