MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
The original Anet A8 has different thickness between vertical and horizontal top frame. The top frame is thinner so and the filament guide won't stay on that.
Your printer is probably a different version, or a newer A8 with different parts!