Steam keeps validating game files tf2
As to why the validation is happening automatically after updates download for these two games.
I don't know, it doesn't make much sense, since the download just happened and should not have been corrupt.
Steam will examine the game’s files and – if any problems are detected – will re-download the corrupted files from Steam’s servers.
To validate a game’s cache, right-click the game in your Steam library and select Properties.
Corrupted files can also cause a multitude of other odd game bugs.
To fix corrupted game files, you can have Steam validate the game’s cache on your system.
If a game fails to load, crashes as soon as it loads, or crashes when you reach a specific level, your game’s files may be corrupted.
Right-click your taskbar and select Start Task Manager to open the task manager.