Today if we detect concurrent modification of a snapshot repository then we mark it with `CORRUPTED_REPO_GEN` which blocks further writes to try and prevent additional damage to its contents. You can remove the marker by calling the register-repository API again, but this API will discard no-op re-registrations without taking any action. You can work around this by unregistering the repository first (which may be impossible if it's still in use for searchable snapshots) or by re-registering it with some trivial setting change (which seems hacky).

We should not consider it a no-op re-registration if the repository is currently marked with `CORRUPTED_REPO_GEN`, because doing this re-registration will re-read the repo contents and clear the corruption marker and therefore is not a no-op.
server/src/main/java/org/elasticsearch/cluster/metadata/RepositoryMetadata.java
return settings.equals(that.settings);
    }
    @Override
    public int hashCode() {
        return Objects.hash(name, uuid, type, settings, generation, pendingGeneration);
    }
    @Override
    public String toString() {
        return "RepositoryMetadata{"
            + name
            + "}{"
            + uuid
            + "}{"
            + type
            + "}{"
            + settings
            + "}{"
            + generation
            + "}{"
            + pendingGeneration
            + "}";
    }
    public RepositoryMetadata withUuid(String uuid) {
        return new RepositoryMetadata(name, uuid, type, settings, generation, pendingGeneration);
    }
    public RepositoryMetadata withSettings(Settings settings) {
        return new RepositoryMetadata(name, uuid, type, settings, generation, pendingGeneration);
    }
}