But then I figured out there was a rating glitch (or maybe server problem) .
Since this glitch can be quite a severe one, so I open a new thread to remind others.
My original rating was 2536 , and I played nine classic matches today, I won all nine of them , six matches were against 2k+ players
And I got +14 points in total throughout all those matches, so my rating should be 2550.
However, my rating dropped to 2493 in a weird way. And the weird dropped happened twice.
The first drop is that, when I was queuing in ranked, and got an opponent, but then the game timeout, I did not even play the game, but I dropped to 2511 suddenly.
And then when I ranked back to 2524 , I met a player called beyen, when I was winning, the server was suddenly down, and I got logged out . After five minutes, the server restored and I was able to log in, but my rating dropped to 2493.
And the more weird thing is that, my win-loss record had two more loses due to this matter and my rating dropped. But there were no replay records after this happened.
I did not get the first drop proof. But I did got the second drop proof


So I am here to remind other players not to play ranked matches due to this matter. And hopefully supporters can deal with this issue as well.