I seem to have the same issue. I have a button: <RadzenButton Click=@(args => UpdatePlaylistTitle()) Text="Save"></RadzenButton> and it doesn't trigger the function. When I copy it into the editor at: https://blazor.radzen.com/button it works and the function is triggered. However, in my project, it is not.
UPDATE:
It seems that the render modes are an issue, not Radzen itself, because a regular blazor button didn't work as well with @onclick. I added @rendermode RenderMode.InteractiveServer to the component and everything started to work. Reading this: Event handlers in layout do not seem to fire in a .NET 8 RC1 blazor application · Issue #50712 · dotnet/aspnetcore · GitHub gave me the idea to try that and it worked.