Advice needed for 'Cannot use multiple context instances within a single query execution. Ensure the query uses a single context instance.'

Question

I've been having an issue with one of my .net core services when using the join statement.

This is the problem code:

public List<Category> GetCategoryList()
{
    var catlist = (from m in _mappingProductCategoryRepository.Table
                   join c in _categoryRepository.Table on m.CategoryId equals c.Id
                   select c).ToList();   
                       
    return catlist;      
}
    

and the error it throws is this:

InvalidOperationException: Cannot use multiple context instances within a single query execution. Ensure the query uses a single context instance.

Here is the relevant excerpt from my repository:

public partial class PSRepository<TEntity> : IRepository<TEntity> where TEntity : class
{
    private readonly PSContext _db;

    public PSRepository(PSContext PSContext)
    {
        _db = PSContext;
    }
    
    public virtual IQueryable<TEntity> Table => _db.Set<TEntity>();
}

And here is my context being registered in the startup.cs file

     public void ConfigureContainer(ContainerBuilder builder)
     {
         builder.RegisterType<PSContext>().As<PSContext>().InstancePerDependency();
         builder.RegisterGeneric(typeof(PSRepository<>)).As(typeof(IRepository<>)).InstancePerLifetimeScope();
         builder.RegisterType<CategoryService>().As<ICategoryService>().InstancePerLifetimeScope();
    }
    

I've changed the context registration from 'InstancePerDependency' to 'InstancePerLifetimeScope' so that it now looks like this:

builder.RegisterType<PSContext>().As<PSContext>().InstancePerLifetimeScope();      

And it seems to have fixed the issue. So being somewhat new to .Net Core my question is whether or not this was the correct fix for the issue? Or have I created further issues for myself further down the line?

I realise I could get rid of the repository and use the context directly but I don't really want to do this.

Any help gratefully received