This has happened to me a couple of times after resuming from suspend (opening the laptop's lid).
Sometimes there is a delay before the lock screen is displayed -- your session is visible for a second or so.
Once I managed to focus on a terminal window before the lock screen appeared, and I was unable to type my password in the password field. I managed to work around this somehow (unfortunately I don't remember how) and discovered that all characters I had typed were entered into the terminal window.
This has happened to me a couple of times after resuming from suspend (opening the laptop's lid).
Sometimes there is a delay before the lock screen is displayed -- your session is visible for a second or so.
Once I managed to focus on a terminal window before the lock screen appeared, and I was unable to type my password in the password field. I managed to work around this somehow (unfortunately I don't remember how) and discovered that all characters I had typed were entered into the terminal window.
Looks like a serious security risk.