No errors and empty read results


I have a strange issue with 3-nodes cluster setup v4.4.4 and Go-driver v1.6.0: in a random amount of time read queries start giving no errors and no result. Mongo logs seems to be OK at that.

Read code looks like this:

func readAllObjects(ctx context.Context, cur *mongo.Cursor) (objects []*dto.DBObject, err error) {
    if err = cur.All(ctx, &objects); err != nil {
        return nil, err
    return objects, nil

As I said the build objects slice is empty. Another service connected to the same cluster returns actual data with the exactly the same input.

Don’t have a slightest idea of what could it be, any hints?