ASTC codec LDR compression bug

When compressing certain textures with ASTC LDR we get corrupted results.

Source image:

Source image (1024x512 lightmap) can also be found attached to post or downloaded here:

https://dl.dropboxusercontent.com/u/7197208/images/lightmap_table-evening.png

When compressed in LDR Linear mode we get corrupted result: top part (2/3rds of image) is clear white and in the bottom source image is repeated 3 times:

When trying to compress image in LDR SRGB we get the following error:

Image is compressed correctly only in HDR mode.

This does not happen with other images, only certain ones  (black-and-white lightmaps) are affected by bug.

Tested on Mali Texture Compression Tool versions 4.2.0 and 4.1.0.

Bug prevents us from using compressed ASTC textures in our Android app, its a shame because it provides excellent quality compared to ETC2 full of block artifacts.