Password/Keyboard issues

[Abe]

When restarting my Mac from sleep, my user name comes up ( administrator privilages) and password is requested. The key stokes I put in fail to appear in the password box, instead random characters ( ......dots) are put in seemingly by the Mac on its own and I am not able to sign in. This happens sevral times a day, but not every single time. The problem is corrected by turning the machine off and then on. This solves the issue for the present, but the same thing happens again after the computer goes to sleep. Anyone has any idea why this happens? This problem started after installing MacOs high Sierra currently on 10.13.4.
The Mac is a 27" built in 2013.

 

[Lufbrarunner]

How do you wake your mac up? If you tap a keys on the keyboard you could inadvertently put a rogue character in the password.

 

[Abe]

I do use the keyboard, but usually the space key or shift. I don't believe that's the problem, but will try to wake Mac up with the mouse to see what hapens.