inexplicable syncing to multiple catalogs

[skyephoto]

First post here, thank you.
I've been teaching Lightroom since 2010. Recently, a student came to me with something I couldn't explain or "correct". She has 2 catalogs, both synced to LR Mobile. Catalog 111001 is her original catalog from 2011. Catalog 180101 was created in 2018 when she ran out of space on her first external drive. When she created it, she gave it the same name as the catalog she had created in 2011 (Master Catalog 111001), but it was on a different drive and there was a different path to it. It synced with mobile and both remained synced after changing the name of the second catalog. As you can tell from the attached screenshots, her organization has a few issues, but nothing that explains how she ended up syncing two catalogs. Any ideas?

[richardplondon]

Since both Catalogs now match the Catalog naming for which LR syncing is configured, both can participate in syncing updates to or from cloud storage.

That's why there is now the same count of synced photos within each one. Even though the numbers of conventionally imported photos may differ.

Just as a comment for this student, "running out of space" on a given storage volume never dictates making a fresh Catalog.

• When the problem is space for image files, that just requires storing future additional image files in a different location, and optionally moving all or some existing image files too. Provided LR is informed about any new locations, the same Catalog can continue to reference them to the same effect, in all respects.
• When the problem is space for storing the Catalog itself with its preview files etc, that can just be moved wholesale to another storage volume, where you can simply pick up using it seamlessly. Such a move of the Catalog is unrelated to, and independent of, any change to image files' location.