Automapper, Entity Framework Core and multiple nested collections

Question

My database has two tables - RuleGroups and Rules. My Entity Framework classes are the following:

public class RuleGroup
{
    [Key]
    public Guid Id { get; set; }
    public string Name { get; set; }
    public ICollection<Rule> Rules { get; set; }
}

public class Rule
{
    [Key]
    public Guid Id { get; set; }
    public Guid RuleGroupId { get; set; }
    public string Name { get; set; }
    public ICollection<Condition> Conditions { get; set; }

    [ForeignKey("RuleGroupId")]
    public virtual RuleGroup RuleGroup { get; set; }
}

[NotMapped]
public class Condition
{
    public Guid Id { get; set; }
    public string Name { get; set; }
}

Class Condition is not mapped because it is being serialized and stored as JSON in Rule Table (using this example)

My DTOS are the following:

public class UpdateRuleGroupDto
{
    public string Name { get; set; }
    public ICollection<UpdateRuleDto> Rules { get; set; }
}

public class UpdateRuleDto
{
    public string Name { get; set; }
    public ICollection<UpdateConditionDto> Conditions { get; set; }
}

public class UpdateConditionDto
{
    public string Name { get; set; }
}

In my Startup.cs I initialize Automapper :

AutoMapper.Mapper.Initialize(cfg =>
{
    cfg.CreateMap<UpdateRuleGroupDto, RuleGroup>();
    cfg.CreateMap<UpdateRuleDto, Rule>();
    cfg.CreateMap<UpdateConditionDto, Condition>();
}

I have an API controller endpoint that accepts JSON PATCH document to make changes to data stored in database.

public IActionResult Patch(Guid ruleGroupId, [FromBody]JsonPatchDocument<UpdateRuleGroupDto> body)
{
    RuleGroup ruleGroupFromRepo = _deviceRules.GetRuleGroup(ruleGroupId);
    UpdateRuleGroupDto ruleGroupToPatch = Mapper.Map<UpdateRuleGroupDto>(ruleGroupFromRepo); 

    // Patching logic here

    Mapper.Map(ruleGroupToPatch, ruleGroupFromRepo);
    context.SaveChanges();

    return NoContent();
}

The problem:

When changes are made/saved, Rules in Rule table change their/get new GUID.

Example, say we have this data in 2 Tables.

  RuleGroup Table
  [Id][Name]
  [ddad5cac-e5a1-4db7-8167-66a6de3b8a0c][Test]

  Rule Table
  [Id][RuleGroupId][Name][Condition]
  [17c38ee8-4158-4ecc-b893-97786fa76e13][ddad5cac-e5a1-4db7-8167-66a6de3b8a0c][Test][[{"Name":"Test"}]]

If I change field [Name] to a new value, Rules Table will look like this.

  Rule Table
  [Id][RuleGroupId][Name][Condition]
  [ba106de8-bcbc-4170-ba56-80fe619cd757][ddad5cac-e5a1-4db7-8167-66a6de3b8a0c][Test2][[{"Name":"Test"}]]

Note that [Id] field has now a new GUID.

EDIT

@Gert Arnold made me realize that I'm not attaching entities. I ran the following code:

  foreach (var item in ruleGroupFromRepo.rules)
  {
    var x = _context.Entry(item).State;
  }

and all the states were Added and not modified. Now I just have to figure out how to do it properly.