Slow degradation of Performance Retrieving Files

Currently using version 4.9.4. Monitoring a Dropbox account every 30 seconds looking for new files. Files come in from multiple sources, usually only 128 bytes in size, but occasionally can be much larger - 5-10 megabytes. Everything works fine for hours, but after 12-16 hours it starts to see socket errors and slows down. Request to download files must be made multiple times on many occasions, and ultimately it pauses and fails. While it's failing the files start to pile up, and it only gets worse. Killing and restarting my C# application doesn't have any effect. If I reboot my PC, it works great again - for 12-16 hours, then it starts. CPU/memory are not an issue. Comcast speeds show around 750MBps (though that is probably BS). Could there be a resource issue, or something I'm not doing?
I'm essentially doing a ListFolderAsync every 30 seconds, using DownloadAsync() to get any files, and DeleteV2Async() after I've retrieved it. I use the same DropboxClient object every time. It could be something in my code, but you would think that killing/restarting it would make the problem go away, which it doesn't. Only rebooting the computer fixes it. Thoughts? (Thanks in advance!)