When a shard is to be snapshotted, we acquire a store ref (wrapped in an index commit) and then enqueue the shard snapshot task for execution by the repository:

https://github.com/elastic/elasticsearch/blob/b124763772748d8993911e4a7ba94b17472a9539/server/src/main/java/org/elasticsearch/snapshots/SnapshotShardsService.java#L369-L384

If the shard is closed while its snapshot is in the queue then it looks like we do not release the store ref promptly. Instead, we keep hold of it until it reaches the front of the queue, which could be many minutes later. During this time the shard cannot fully shut down and release the shard lock, leading to a `ShardLockObtainFailedException` being thrown on attempts to reinitialise the shard.
server/src/main/java/org/elasticsearch/index/snapshots/IndexShardSnapshotStatus.java
}
    public synchronized Copy moveToStarted(
        final long startTime,
        final int incrementalFileCount,
        final int totalFileCount,
        final long incrementalSize,
        final long totalSize
    ) {
        if (stage.compareAndSet(Stage.INIT, Stage.STARTED)) {
            this.startTime = startTime;
            this.incrementalFileCount = incrementalFileCount;
            this.totalFileCount = totalFileCount;
            this.incrementalSize = incrementalSize;
            this.totalSize = totalSize;
        } else if (isAborted()) {
            throw new AbortedSnapshotException();
        } else {
            assert false : "Should not try to move stage [" + stage.get() + "] to [STARTED]";
            throw new IllegalStateException(
                "Unable to move the shard snapshot status to [STARTED]: " + "expecting [INIT] but got [" + stage.get() + "]"
            );
        }
        return asCopy();
    }
    public synchronized Copy moveToFinalize() {
        final var prevStage = stage.compareAndExchange(Stage.STARTED, Stage.FINALIZE);
        return switch (prevStage) {
            case STARTED -> asCopy();
            case ABORTED -> throw new AbortedSnapshotException();
            default -> {