I’ve not tested the impact of the following code https://github.com/percona/percona-backup-mongodb/blob/main/pbm/snapshot/restore.go#L110-L120 but it looks like it tries to merge 2 slices incorrectly and as a result, it ends up with the “old” slice being used (the one created in the if-bloc is dropped at the end of it).

Due to this behavior defined config collections are never excluded (https://go.dev/play/p/Yq4Sna5pVCI )