This refers to that issue: https://github.com/owncloud/core/issues/26071
I just verified that this still/also exists in NC10. I was able to reproduce the issue by setting up a vanilla NC10 installation with a new/empty MySQL DB. The only additional plugin I’ve enabled is “External storage support 1.0.2”. I added a local (same server) SMB share (containing a lot of files) and after a while the “backup detected” issue occurs.
Any chance that will get fixed in NC10 some time soon? For me that makes NC/OC more or less useless as all my data is contained in “external storage” accessed via SMB.