A Microsoft file hosting and synchronization service.
Dear Wesley Hughes,
Yes, this behavior can be related to OneDrive Files On-Demand. The blue cloud icon means that the file is currently online-only and is not stored locally on your computer
Normally, opening an online-only file downloads it and makes it locally available. If the file later returns to a cloud icon, Storage Sense may be making locally available files online-only again based on its configured settings.
As a test, please right-select one affected file in File Explorer and select Always keep on this device. Then check whether the file displays a green circle with a white check mark and remains available after closing and reopening OneDrive or File Explorer.
Also, please let me know whether the file changes to a green check mark when you first open it and then returns to the cloud icon later, or whether it continues showing the cloud icon immediately after you open it.
Thank you for your cooperation. Looking forward to hearing from you!