from the patch notes:
Rewards

Treasure coffers that appear upon completing Omega: Sigmascape (Savage) will yield gear.

If your party contains players replaying an area prior to the weekly reset, the number of treasure coffers appearing upon completion will decrease. Furthermore, players will be ineligible for rewards from treasure coffers as well as Sigmascape datalogs when replaying an area prior to the weekly reset.
* If there are one to four players in your party replaying an area, only a single treasure coffer will appear. If there are five to seven players in your party replaying an area, no treasure coffers will appear.

if you entered a higher floor then go back to a previous one you are considered cleared. you normally cannot enter a higher floor without progression first so someone else took you in to a higher floor. only when loot/progression is unlocked is when you can freely farm gear and tokens. this typically does not happen until the next patch.