The Mystery of Missing Supplies
In Prodromos, enter the bottom floor of the northern-most two story structure and read the message "Prodromos supplies report" on a Terminal to start this quest. Once done, note the numerous navpoints on your map and head to any one of them - there’s one near the Forward Station near the third monolith, one west of Site 2, one near a Forward Station northwest of Prodromos, and another near a fork in the road west, southwest of Prodromos.
Go to any one of these navpoints and you’ll find bugs - several Shemrys, to be precise - where the supplies were supposed to be. This apparently satisfies the conditions of the quest, enough so you can return to the Terminal in Prodromos and log the loss info (this will earn you 270 XP, 29 AVP and +2% Eos viability)… but if you’re more diligent, perhaps there’s more to this?
Kill the bugs at each site and scan the Supply Drop Site to learn that the random actions of Eos pests wasn’t solely responsible for the losses recorded. After scanning the last wreckage, you’ll lose the ability to simply report the losses for an easy reward, but you’ll get a new navpoint to explore in return. This navpoint is due east of the northwestern-most supply drop navpoint, near a Forward Station northwest of The Sheartop Forward Station, which itself is northwest of Prodromos.
Exoneration or Exile on Eos
From this Forward Station drive south, then east through a cave. Follow the trail on the eastern side of the cave as it turns south and when it turns east again, veer off the road to the southwest up a rocky slope. Turn west until short but sheer cliffs block your progress, then turn north and ascend another slope. Drive north to the navpoint and you’ll find a small camp in a depression, where, after some threats, the thieves will consent to parley. Chase Gagnon - the leader of the thieves - will chat with you and you’ll eventually get to make a choice: send the repentant exiles back to Prodromos, or kick them off Eos. Either way, you’ll need to return to Prodromos and log a report at the terminal to complete the quest. If you did the extra legwork you’ll get 530 XP, as well as 29 AVP and +2% Eos viability.