Are d-vectors between speakers same?

hello, sir 
I have run your project use aishell data,  after trainning ,dev ge2e loss is 0.15 (begin is 3.44).
but when i compute the d-vector , I found the d-vectors between speakers look alike，and cosine of all d-vectors are 0.99……，so, is it right? and do you have some suggestions for me ?
thank you 