Unable to type Other User username or password for Windows 10 login

Make sure the CAPS LOCK is off and the NUM LOCK is on.

You can check for a malfunctioning keyboard by using the Ease of Access keyboard to enter the password. On the computer log in screen place the cursor in the password entry box, click the Ease of Access icon (third icon from left bottom right corner of screen), click On Screen Keyboard and enter password using that keyboard,

Why can't you sign in?

https://account.live.com/password/reset

If you choose to select I've forgotten my password that the email Microsoft sends you goes to an email address you can access that does not depend on gaining access to the problem computer.

Make sure the CAPS LOCK is off and the NUM LOCK is on.

You can check for a malfunctioning keyboard by using the Ease of Access keyboard to enter the password. On the computer log in screen place the cursor in the password entry box, click the Ease of Access icon (third icon from left bottom right corner of screen), click On Screen Keyboard and enter password using that keyboard,

Why can't you sign in?

https://account.live.com/password/reset

If you choose to select I've forgotten my password that the email Microsoft sends you goes to an email address you can access that does not depend on gaining access to the problem computer.

The login issue has nothing to do with keyboards or passwords; those all work fine. There is no box to type in a username or password. Only when I restart the computer am I able to type in the username and password box.

Notice no boxes to type in.

I am the IT Specialist for a SMB and have noticed the same issue crop up on a few of our computers as well, specifically over the last two of weeks. We run delayed updates, and there doesn't seem to be a rhyme or reason with a specific Windows Update triggering the glitch, as some computers are on older and some on newer builds, and it's a mixed bag of who's affected. Every time it's happened a reboot has solved it, but I'm hoping for a faster or more permanent solution. 

We use a Windows Domain, and when a user needs to log in they click the "other user" option. For a very small, random smattering of instances the Other User will pop up with a password field but no username field to type in. Being unable to type in their username means they are unable to log in, as both fields are required. Typically the previous user has left for lunch and may have open programs, so rebooting the computer is not an ideal solution. 

I've tried Googling everything I can think of for this issue and this is the first matching example I've been able to find after half an hour of looking. I wish I could contribute a solution, but hopefully someone else posting here will up the chances of one being found. 

Thank you!