When using a billboard component to display a texture in 2d, I noticed that when running on android, or using mobile preview ES2, the texture displayed is considerably darker than it should be.
(Correct colour on the left, darkened colour while using mobile preview on right)
Enabling mobile HDR corrects it, but comes at a large performance cost. Using material billboard components also can correct it, but again there is a noticeable performance cost in doing so. The issue only seems to happen with billboard components.
Disabling sRGB on the texture causes it to appear correctly on Android and mobile preview ES2, however it then appears extremely washed out when playing in editor. It will also display this same washed out version when used in UMG while playing in editor and iOS. On android, disabling sRGB makes it display correctly at all times.
It seems like the gamma correction is causing it to display incorrectly?
I have made a simple project to show the problem, just play using mobile preview to see the issue https://drive.google.com/open?id=1QgCZncD7MBZ56wybD_5VRgul3AmY2k6a