It is probably a usual thing that a file got corrupted in memory and usually just a reboot will fix that. Would think it was random especially if was a while since you rebooted. There is a MS Windows Dos command you can run to fix corrupted files on your system which is described here : https://www.howtogeek.com/222532/how-to-repair-corrupted-windows-system-files-with-the-sfc-and-dism-commands/ Please note that Microsoft is forcing all systems running Win10 version 1803 (which your running) to version 1903 https://www.techspot.com/news/81005-microsoft-starting-force-update-windows-10-machines-version.html

This can happen if you have security software with an anti-keylogger feature enabled. Known security software from the past includes Zonealarm.