MacBook Pro mid2012 switching between keyboards get incorrect letters

Hello. I have a macbook pro mid 2012, updated to high sierra 10.13.3.

I use 3 input language on my macbook - Chinese, English, and russian, and after the update to 10.13.3 I noticed a strange feature.

I've had a concern with switching between keyboards and getting the correct letters. Only since the most recent update.

When I type in Chinese no problem, but when I change the keyboard layout from Chinese to Russian and try to type in Russian - it still gives out Latin letters.

Every time I want to type in Russian after Chinese, at first I have to switch the layout from Chinese to English, then from English to Russian and only that strange manipulation i can normally type in Russian. I try delete the Chinese, then everything switches normally, but i need chinese layout.

I also tried to use input method software from the other developers - for example pinyin.sogou.com, but it still does not work.

P.S. i try it all on my wife's macbook too, before the update everything was ok, but after updated to high sierra 10.13.3 - the same problem arose.

the steps recommended by apple support that I did

- create a test user, to see if it can duplicate the issue

- reboot in safe mode

- SMC reset

- NVRAM reset

the issue still happening !!

the last advice of apple support

"Sounds like we do need to reinstall macOS on both Mac books and see how that resolves the issue. We’ll certainly get to the bottom of this!"

They thinks that the issue because update was not installed correctly

I understand this happens, but how it could occur on two different MacBooks equally.

The probability is very low that on two different MacBooks the update was not installed correctly and an identical error appeared.

i can reinstall mac OS but they not sure it can help me

apple support said:

"If those steps to reinstall macOS do not resolve the issue on either MacBook, we may need to erase the hard drive, and then reinstall macOS again. Then you can restore your data. Its possible if you use Time Machine the issue could return. If this happens, we could have to restore data separately."

I believe that this error can be corrected as something different - not in such a complicated and dangerous way