Online-Only folder setting fails to persist

I just started using Dropbox desktop app, and I am moving about a terabyte of files into online-only storage.

I have a folder that I am putting batches of files in as I get them organized, and so that I'm syncing in batches instead of doing it all at once.

Here is the issue: The folder that I am placing files in keeps changing from Online-Only to Available Offline. Each time I add a new bunch of files to it, I have to right click and re-select Online-Only. Then it removes the files from my computer and I see the cloud icon instead of the blue checkmark.

However the next time I move files into the folder from my hard drive, it changes back, and after the files are synced I have to once again right click and change the folder to Online-Only.

I have the default sync state for new files set to Online-only, but I don't know if a "new" file is just one that is new to my Dropbox folders or one that I create within Dropbox. 

Either way, once I manually set a folder to Online-only, I want it to stay that way, regardless of what files I move into/out of it.

Any help would be greatly appreciated. Thanks!