EntityFrameworkCore using wrong column in query

I am trying to write my first web api with .net core. I am using VS2017 and core 1.1. I've got everything working except for one of my objects (I've tried it with that last line commented and uncommented...it makes no difference):

public class Tag
{
    public int ID { get; set; }
    public string Name { get; set; }
    public bool ShowInFilter { get; set; }
    public ICollection<SubscriberTag> SubscriberTags { get; set; }
}

My repository code looks like this:

private SubscriptionContext db;
public TagRepository(SubscriptionContext context) { db = context; }
public Tag Find(int key) => db.Tags.SingleOrDefault(a => a.ID == key);

That is being called from my TagController:

private iTagRepository TagItems { get; set; }
public TagController(iTagRepository tagItems) {TagItems = tagItems; }

[HttpGet("{id}", Name = "GetTag")]
public IActionResult Get(int id) { return new ObjectResult( TagItems.Find(id) ); }

The problem is when I run it, the query that is executed is:

exec sp_executesql 
N'SELECT TOP(2) [a].[ID], [a].[Name], 
    [a].[ShowInFilter], [a].[SubscriberID]
FROM [Tags] AS [a]
WHERE [a].[ID] = @__key_0',N'@__key_0 int',@__key_0=1

which throw and error because Tags doesn't contain a column called SubscriberID. I've searched all my code and SubscriberID only shows up two places (in other classes which are not being used here). I have no partial classes in my entire project (saw that was an issue on a related question.)

Why is EF adding this column to its query and how do I fix it?

As requested here is the class that contains subscriberID:

public class SubscriberTag
{
    public long ID { get; set; }
    public long subscriberID { get; set; }
    public int tagID { get; set; }

    public Subscriber Subscriber { get; set; }
    public Tag Tag { get; set; }
}

Subscriber class (lots of irrelevant properties removed):

public class Subscriber
{
    public Subscriber()
    {
        //a few value initalizers/defaults
    }

    public long ID { get; set; }
    [StringLength(200)]
    public string FirstName { get; set; }
    //.......

    public ICollection<Subscribers.Models.Subscription> Subscriptions { get; set; }
    public ICollection<Subscribers.Models.Tag> Tags { get; set; }
}