When you are using Capture One session, Peakto will ingest your files from the data stored in the C1 database.
So if you make some changes in your session, directly using the finder and if you want to see your changes in Peakto, you have to:
1) reopen C1: it will update its database with your changes
2) Make a Smart Re-Ingest in Peakto to let Peakto update your changes.
For that make CTRL click on your source and choose smart Reingest.