File Sharing Microsoft Teams

ghernandez2022 It's usually caused because they are using their own downloaded copy and save over the existing copy. Or they do not use "Autosave" feature and have it open for extended periods and then manually save their copy over someone elses. 

Either way, def. someone not utilizing co-authoring features of todays modern tools. Need to make sure they are using Auto-Save so they are working "Live" on documents, or use browser versions to edit, especially higher traffic documents.  

I know some people just work in their ways, and it's hard to change but that is most likely your issue going on, someone in the bunch and you should be able to tell who based on history of saves to see who wiped stuff out and educate them on how to properly work in documents in a coauthored environment, or follow up and make sure they don't have auto-save off etc or some other issue going on.