Abrupt bouncing values in scattering rate

Dear Alex,

I am now calculating the Bi2Se3.

While checking the energy vs scattering rate graph, I can see values that suddenly jump at a specific energy point.

Here is the question. Is there a rule of thumb to check if this is correct or an error?

I’m not sure where to start and how to check if this is a “calculation error” or “real physics”.