After locking the screen in Ubuntu 14.04, password is not accepted, How can it be fixed?

I'm running Ubuntu 14.04 fully updated on my laptop. Since the last update every time I lock the screen (when leaving my room for example) - when I get back and input my password, it is not accepted even though it's the correct password, the error I get is:

Password incorrect, please try again

I found that clicking the "Switch Account" fixes the issue but it is very annoying, if you know any way to fix it, it would be nice. Thanks in advance

I've found that in some cases the input language is set to Hebrew even though it shows a "EN" icon in the gnome systray, hitting the input language changer sequence does nothing visibly but when I enter the password again it works.

Have the same issue with 16.04.

I know it might not be the perfect solution, but the trick is to simply click on the switch user button in the right corner. Put in your password and it works.