I'm getting the following error depending on the position of my code block, why would Umbraco throw an error when the code is inside HTML markup, but not when it's outside of HTML markup?

No error:

{
    if (project.HasValue("projectCategories"))
    {
        var typedMultiNodeTreePickerCSV = project.GetPropertyValue<string>("projectCategories");
        var typedPublishedMNTPNodeListCSV = typedMultiNodeTreePickerCSV.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse);
        var typedMNTPCollectionCSV = Umbraco.TypedContent(typedPublishedMNTPNodeListCSV).Where(x => x != null);
        foreach (var item in typedMNTPCollectionCSV)
        {     
            <p>@item.Name</p>         
        }   
    }    
}
    
  <div class="item @itemSize @stamped @spacer" style="@xPos @yPos">
       <a href="#" class="overlay">
        <div class="overlayHeading">
            <h1>@project.GetProperty("title").Value</h1>
            <h2>@project.GetProperty("projectCategories").Value</h2>
        </div>
                  
        @if (@project.GetProperty("thumbnailImage").Value != null){                                         
            
          <img src="@dynamicMediaItem.umbracoFile" alt="@dynamicMediaItem.Name"/>
     }
     </a>
    </div>

Error:

<div class="item @itemSize @stamped @spacer" style="@xPos @yPos">
      <a href="#" class="overlay">
        <div class="overlayHeading">
            <h1>@project.GetProperty("title").Value</h1>
            {
               if (project.HasValue("projectCategories"))
                {
                 var typedMultiNodeTreePickerCSV = project.GetPropertyValue<string>("projectCategories");
                    var typedPublishedMNTPNodeListCSV = typedMultiNodeTreePickerCSV.Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries).Select(int.Parse);
                 var typedMNTPCollectionCSV = Umbraco.TypedContent(typedPublishedMNTPNodeListCSV).Where(x => x != null);
                    foreach (var item in typedMNTPCollectionCSV)
                  {     
                        <p>@item.Name</p>         
                    }   
              }    
         }
        </div>
                   
        @if (@project.GetProperty("thumbnailImage").Value != null){                                         
            
          <img src="@dynamicMediaItem.umbracoFile" alt="@dynamicMediaItem.Name"/>
     }
     </a>
    </div>