With version 11.2.3 the following error shows up in browser console:
rit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
Unhandled exception rendering component: The value 'Radzen.createSplitButton' is not a function.
The page code most likely to cause it:
<RadzenSplitButton Icon=get_app Text=Export Click=OnExportClick Variant=Variant.Flat Shade=Shade.Lighter Visible=@(!IsChildDataGrid && (Security.IsInRole("Operator")))>