Stanley,
After changing the copyright in images through the database catalogue the changes are made in the file, but they continue to show up in the search as not being changed. It appears that you have to then rescan them into the database to make that work for future searches.
That isn't really a good fix. Once you make a change the database should automatically have updated.
If the images are known to the catalog then metadata changes to the files (by making changes in Photo Mechanic Plus) will be reflected in the catalog. It sounds like to me that some sort of operation was done by you that has (likely by way of a bug in Photo Mechanic Plus) caused the catalog to lose track of the images. Working with images that are currently tracked should be completely painless and should not require rescanning.
This product is still under development, is likely to have bugs or missing features. We need your help to find out what went wrong and then we'll make changes to prevent such inconveniences in the future.
If you look at the images that you're finding that you need to rescan into your catalog, to they have a green circle on them, or do they have a hollow gray circle? If they don't have a green circle then they're not known to the current catalog(s). Making metadata updates to those files will make no updates in any catalog.
Your help in finding out how to reproduce your problem is most appreciated.
-Kirk