Normals and SpriteAtlases - Serious Bug?

I'm using a Sprite with normal channel (_NormalMap) added via SecondaryTextures (sprite editor). It works well until I actually drop that Sprite into "Objects for Packing" field under Sprite Atlas.

The sprite is affected by 2D lights that have "Use Normal Map" field checked, without that enabled the issue doesn't appear at all (hence the conclusion that it has to do with how normal map channel and atlas interacts)

before adding to atlas:

after adding to atlas:

It's as if the _NormalMap channel gets stretched to the Atlas size which produces those artifacts

Any idea if there's a way of fixing it? (I know you can make your own atlas in photoshop and then use Sprite Mode: Multiple and it should work around the issue, but that's downgrading the workflow a lot)

Edit: If that Sprite is the only thing in the atlas this doesn't occur, so it is stretching the normal after all.

 

I received an email after sending in a sample project with the bug reproduced, the title contains "(Case 1167829)" so I guess that must be the ID you requested.