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/repositories/RepositoriesService.java
);
    private final Map<String, Repository.Factory> typesRegistry;
    private final Map<String, Repository.Factory> internalTypesRegistry;
    private final ClusterService clusterService;
    private final ThreadPool threadPool;
    private final VerifyNodeRepositoryAction verifyAction;
    private final Map<String, Repository> internalRepositories = ConcurrentCollections.newConcurrentMap();
    private volatile Map<String, Repository> repositories = Collections.emptyMap();
    private final RepositoriesStatsArchive repositoriesStatsArchive;
    private final List<BiConsumer<Snapshot, Version>> preRestoreChecks;
    public RepositoriesService(
        Settings settings,
        ClusterService clusterService,
        TransportService transportService,
        Map<String, Repository.Factory> typesRegistry,
        Map<String, Repository.Factory> internalTypesRegistry,
        ThreadPool threadPool,
        List<BiConsumer<Snapshot, Version>> preRestoreChecks
    ) {
        this.typesRegistry = typesRegistry;
        this.internalTypesRegistry = internalTypesRegistry;
        this.clusterService = clusterService;
        this.threadPool = threadPool;
        
        
        if (DiscoveryNode.canContainData(settings) || DiscoveryNode.isMasterNode(settings)) {
            if (isDedicatedVotingOnlyNode(DiscoveryNode.getRolesFromSettings(settings)) == false) {
                clusterService.addHighPriorityApplier(this);
            }
        }