On Feb 21st 2018, I was flying from Iceland to SFO and right before we took off, I saw these guys taking bags off of the plane. I didn't see where they went with them, but a few days after we landed, the person sitting next to me said her bag was delayed by a few days. I sent her this video, and low and behold, one of those bags coming off of the planes was hers.
This happened on the flight from SFO to Iceland. I think it's because they downsized our plane and needed more fuel for the long haul. Over 60 people also didn't have their bags for 5+ days. I guess that's what happens when you downsize your plane to save on cash but still have to go a long distance, they have to choose between getting people there versus getting bags there.