Dealing With Product Bundles In Plugin

Hi

I have a plugin registered against opportunity product on create and on update. This works fine. However it errors if the user adds a bundle. So I have attempted to exit the plugin at the earliest opportunity if the product being added is a bundle. However I am now getting a general error saying

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and the bundle is not saving. If I run the code through the debugger it looks to be returning as intended if the product is a bundle. Anyone know what is going on here?

Code snippet below.

                if (context.PostEntityImages.ContainsKey("PostImage"))
                {
                    postImage = (Entity)context.PostEntityImages["PostImage"];
                    product = postImage.GetAttributeValue<EntityReference>("productid");
                    if (product.Name.Contains("BUNDLE"))
                    {
                        return;
                    }

                }