Hi JoshuaMarshall,
I would like to explain that, by design, the OneDrive for Business sync client being used will periodically check files from both cloud and local, and sync to keep the data being updated. During the sync, the file will be occupied by the client before the sync completely fininshed.
Therefore, when working on a document, it is recommended that we temporarily edit it outside the OneDrive for Business folder, and copy it back after finished.
We appreciate your understanding and efforts.
Best Regards,
Rene