Quite possible your Need Roll was met with someone that was also your same job
then it was a 50/50 split : high roll wins.

Even though you say the person was not the same job.. I question whether you based you information on what gear this person was wearing ?

If your Armory was 100 % full the game defaults by placing any equipment obtained into your Inventory. If your Inventory is 100% full as well you will get a message :
( item name ) was lost unable to obtain.

In the case of Lotted / Rolled items.. ( Need ) will always cancel Greed.

There is only one other thing that could have happened: That is you already obtained this item B4 and put it into your Storage / Retainer and forgot that you have it.

This happens all the time on AK runs for me.. the message will say I can not have 2 of the same item.