Issues with select in LINQ2SQL

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Linq2Sql

EF-Core

Hello friends! Here are my entities:

public class Subscription
{
    [Key]
    public int id { get; set; }

    public string name { get; set; }
    public double data { get; set; }
}

public class SubscriptionData
{
    [Key]
    public int id { get; set; }

    [ForeignKey("subscription")]
    public int subscriptionId { get; set; }
    public virtual Subscription subscription { get; set; }

    [ForeignKey("company")]
    public int companyId { get; set; }
    public virtual Company company { get; set; }

    public double price { get; set; }
}

public class Company
{
    [Key]
    public int id { get; set; }
    public string name { get; set; }
    public ICollection<Client> clients { get; set; }
    public ICollection< SubscriptionData > subscriptions { get; set; }
}

public class Client
{
    [Key]
    public int id { get; set; }


    [ForeignKey("company")]
    public int companyId { get; set; }
    public virtual Company company { get; set; }

    [ForeignKey("subscription")]
    public int? subscriptionId { get; set; }
    public virtual Subscription subscription { get; set; }
    public string name { get; set; }
}

There is. a

SubscriptionData

wrapper because every company can have multiple prices for the same subscription.
Now, I am trying to just return list of clients with some calculated values.
I have it like this:

What I have tried:

I start with IQueryable<company> companies, this is returned by repository, and then do this:

companies
.Include(company => company.clients).ThenInclude(client => client.subscription)
.Include(company => company.clients).ThenInclude(client => client.company).ThenInclude(company => company.subscriptions).ThenInclude(data => data.subscription)
.Include(company => company.subscriptions).ThenInclude(data => data.subscription)
.Select(company => company.clients
    .Select(client => new 
    {
    proposedSubscription = client.company.subscriptions.FirstOrDefault(data => data.subscription.data < client.subscription.data)
    }))

So I want to return all clients, with a new proposed subscription, which has less data then current client's subscription. I have one company and this company has 194 users. This condition:

proposedSubscription = client.company.subscriptions.FirstOrDefault(data => data.subscription.data < client.subscription.data)

is met for 4 clients.
But instead of getting 194 clients with 4 proposed subscriptions and rest of them with proposed subscriptions set to null, I get only 4 clients returned.
If I change the condition to:

proposedSubscription = client.company.subscriptions.FirstOrDefault(data => data.subscription.data < 10000)

I get then 194 clients, 4 with proposed subscription object and rest with proposed subscription object set to null.
I do not understand this behaviour of LINQ 2 SQL.
Can someone please explain what I am doing wrong?