The sRGB flag is enabled when importing hdr files. This is disabled in PostEditChangeProperty, but remains enabled if we do not edit the file.
 I think the sRGB flag should be disabled for hdr images.
The following files included in the engine content are also enabled for sRGB.
/Engine/MapTemplates/Sky/DaylightAmbientCubemap.DaylightAmbientCubemap
/Engine/EditorMaterials/AssetViewer/EpicQuadPanorama_CC+EV1.EpicQuadPanorama_CC+EV1
1. Export "/Engine/MapTemplates/Sky/DaylightAmbientCubemap.DaylightAmbientCubemap" to .hdr image
 2. Import that image into the project
 3. The compression setting for the file is HDR, but the sRGB flag is enabled.
[Link Removed]
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-82301 in the post.
| 1 | 
| Component | UE - Editor - Content Pipeline - Import and Export | 
|---|---|
| Affects Versions | 4.23 | 
| Target Fix | 5.0 | 
| Created | Oct 23, 2019 | 
|---|---|
| Resolved | Oct 13, 2021 | 
| Updated | Jan 26, 2023 |