You need to check if the blocks are published, here's is how you can do it:

var blockType = contentTypeRepository.Load<RequisitionBlock>();

var contentUsages = contentModelUsage.ListContentOfContentType(blockType);

var contentReferences = contentUsages.Select(x => x.ContentLink.ToReferenceWithoutVersion()).Distinct().ToList();

var instances = new List<IContent>();

foreach (var contentReference in contentReferences)

{

var content = contentLoader.Get<IContent>(contentReference);

var isPublished = contentRepository.TryGet<IContent>(contentReference, out var publishedContent);

if (isPublished)

{

instances.Add(publishedContent);

}

}

I didn't realize there was an IsDeleted property and this fixes my problem:

var instances = contentReferences
                .Select(contentReference => contentLoader.Get<IContent>(contentReference))
                .Where(content => content != null && !content.IsDeleted)
                .ToList();