Hey pal, I used to have the same issue. Very frustrating when you don't know what causes it. All you need to do though is use a mods folder and make sure you've installed OpenIV.asi (you can find it under the tools tab in OpenIV). If you do that, OpenIV actively protects your files from being deleted by the auto-updater in rockstar's launcher. It has nothing to with this pack though, you'll find that any pack you install will do this if you don't follow those instructions. Welcome to GTA modding! 😄