OpenEXR bugs

[00Ghz]

Hi,

I tried yesterday and today to get a multilayered openEXR file to open in AP for Windows(using latest non beta version)
. I didn’t use it before for this on Win, so no idea how it should behave.

I encounter 2 main issues and they seem related somehow. I can’t get the alpha layers to work as a mask. I also tried the premultiply option from the preferences color menu, and various other settings combinations. That also doesn’t do anything. The alpha channels simply don’t work, all I get is black instead of the transparency. Also sometimes the alpha thumbnail previews only show white everywhere, instead of only the area where the object should be visible. 
I am not messing around with the color channels in the channels panel either.
 

Any ideas of what’s going on? Attached the file.

https://drive.google.com/file/d/0B73kwUgXIf8MclNZb2NJZ2lZbG8/view?usp=sharing

Thanks