Issues with exporting sunset photos from Lightroom

[Wade Abadie]

I discovered this issue for the first time this week. I had a batch of several sunset photos I recently took and did my normal editing/exporting procedure in Lightroom. I always export two versions....a full-resolution version and a second lower resolution version, in which I limit the file size to 2 MB for sharing on the forum and on my phone. My full-res versions look just fine. However, when I exported the low-res versions, there are very obvious and noticeable wavy lines surrounding the sun radiating outward like ripples in a pond (see first reference photo below).

Additionally, I took the full-res version and resized it to a similar file size using different software (PowerToys Image Resizer) and had no issues with that method (see second reference photo below). I can only assume this is a result of Lightroom's method for downsizing during export. Has anyone else noticed this or something similar?

Here are the photos for reference:

Lightroom low-res export

PowerToys resized version

 

[Wes Peterson]

Its a jpeg artifact. You can get around it by adding a little bit of noise.

 

[Nimi]

I discovered this issue for the first time this week. I had a batch of several sunset photos I recently took and did my normal editing/exporting procedure in Lightroom. I always export two versions....a full-resolution version and a second lower resolution version, in which I limit the file size to 2 MB for sharing on the forum and on my phone. My full-res versions look just fine. However, when I exported the low-res versions, there are very obvious and noticeable wavy lines surrounding the sun radiating outward like ripples in a pond (see first reference photo below).

Additionally, I took the full-res version and resized it to a similar file size using different software (PowerToys Image Resizer) and had no issues with that method (see second reference photo below). I can only assume this is a result of Lightroom's method for downsizing during export. Has anyone else noticed this or something similar?

Here are the photos for reference:

Lightroom low-res export

PowerToys resized version

It's banding, common in skies shot in or compressed to 8-bit, eg jpeg.