2018 Honda Accord Touring 1.5L - At around 800 miles, I noticed the passenger seat shifting from left to right, or right to left, when undergoing a continue corner at speed (e.g. green light right turn <20 mph). The shift, while subtle, is definitely felt by the passenger and heard from anyone in the car.

Over time, the amount of shift and noise increased, so I took it to the dealer. I wanted to ensure the seat was properly fastened. They heard the noise, felt the shift, informed me the seat was indeed fastened properly, though they couldn't find the noise origin in the seat. So they replaced the entire passenger seat. The noise was gone with the new seat, but after roughly 800 miles again, the noise and shift are back. This issue is continually getting worse as drive time increases.

Update from Sep 3, 2018: Upon taking it to the dealer for a third time, it appears that they may have found the issue. The dealer noticed that the seat weight sensor determining if someone is sitting in the seat had scratch marks on its connection to the seat frame. They installed foam and tightened those bolts which stopped the noise. We have been using the car with this fix for roughly 3 months now without any issue or noise. This is the longest any fix has worked with this issue, so it appears that was the fix. I will update this post if there is any other issue that comes back