Metadata downloading weird behavior

[excaliber]

Hi all,

I'm experiencing the following issue when downloading metadata:

In "Configure Metadata download" window I have activated other sources besides Amazon and Google such as Edelweiss, Goodreads etc. in order to get a variety of suggested covers. But often and even I have entered the correct ISBN Calibre suggests the wrong books!. When I uncheck every other source except amazon and google then calibre suggests the right book. Why is this happening? Calibre should suggest more books when I have more sources checked, or not? The "Cover priority" is also affecting what kind of metadata and from where are downloaded. Often I have to experiment with the sources and the priority in order to get the right metadata.