Some content in lists disappears

Hi,

We have EPi CMS 11.8.0 running in Azure and we have a strange issue there with some content.

This is the setup:

Startpage
 -has a content area with some blocks

QuoteListBlock
 -has property public virtual IList<ContentReference> Quotes { get; set; }
  -Quotes references 2 QuoteBlock

Now the issue. I think it happens when we deploy code but not sure. 
The code loops through all blocks in Startpage.ContentArea and fetches all blocks by this:
var contentData = _contentRepository.Get<ContentData>(areaItem.ContentLink);

But when I get back the QuoteListBlock the Quotes property is empty. Even though it has blocks when I look in the CMS.
And after a while, even without deploy, when I edit the QuoteListBlock there are no content references. They are gone.

Have anyone seen this before? I don't know where to start looking.

Thanks,
Rickard