You can read how rewards calculation and distribution works on LooksRare here: https://docs.looksrare.org/about/category/rewards
LooksRare rewards its users for buying and selling NFTs on their marketplace.
Gem allows its users to buy and sell NFTs via multiple marketplaces, including LooksRare.
When a Gem user buys assets listed on LooksRare (items that have a LooksRare logo on the top left), they are using Gem contracts to buy from LooksRare marketplace, hence ALL the buy rewards come to Gem contracts.
When a Gem user sells assets on the LooksRare marketplace via Gem, users are directly interacting with the LooksRare marketplace, hence ALL sell rewards are awarded to the users themselves and users can claim them on the LooksRare "Rewards" page.
NOTE: Going forward, Gem would add a button to claim sell rewards from the Gem rewards page itself, so that users don't have to jump to different websites.
LOOKS rewards are calculated for trades done each day until 9 AM PST.
We check the trades (volume) that are done on LooksRare marketplace via Gem by each user. We also check the amount of LOOKS reward received for that day and then calculate the pro-rata amount each user has earned for that day.
Yes, users can claim their rewards whenever they want to do so. All the un-claimed rewards are rolled over.