Key combinations CTRL+SHIFT+D/E/F not working I found that the key combinations Ctrl-Shift-D/E/F somtimes are not working

I really do not know what caused this, but a few tests are as follows,


Restart the computer or logging out and back in is the only two ways I know to temporarily solve the problem, but the issue comes back after some period (no idea what triggered this);
The hardware is OK (I think). I used the Keyboard Viewer and can see that only these three combinations have problems. Specifically, I can see that when SHIFT and CTRL are pressed, pressing D,E,or F has no response. Others are fine, for example, CTRL+SHIFT+T works fine;
While on screen saver, the key combinations works fine while I experiment on the passwords I typed. 


How can I resolve this?

PS: I recently updated to Mojave, but I recall that the issue happened once before the update. Also the model is MacBook Pro (Retina, 13-inch, Late 2013), and currently I'm not using an external keyboard. (I just tried plugging in another keyboard, still not working.)
I just found out that the problem is caused by Sougou Pinyin, a Chinese input software, who recently updated itself with some features along with these new shortcut keys as shown below (pls excuse the Chinise interface)

(Obviously I missed the shift+cmd+E).
Now I have disabled them all.