Incorrect ordering for a findAll operation on a scoped model with predefined order

What are you doing?

I have a Model TheModel with a scope scoped containing order , say order1. On invoking a findAll with an order, say order2, the resulting order is order1, order2

// MINIMAL, SELF-CONTAINED code here (SSCCE/MCVE/reprex)
TheModel.addScope('scoped', {
  order: [
    [associatedModel1, 'foo', 'ASC'],
    [associatedModel2, 'bar', 'ASC'],
  ]
});

scopedModel.findAll({
  order: [
    ['field1', 'ASC'],
    [associatedModel1, 'foo', 'ASC'],
  ]
});

What do you expect to happen?

Resulting order: ORDER BY field1 ASC, associatedModel1.foo ASC (This was the actual order using sequelize version 3.30.4)

What is actually happening?

Resulting order: ORDER BY associatedModel1.foo ASC, associatedModel2.bar ASC, field1 ASC, associatedModel1.foo ASC

Environment

• Sequelize version: 5.15.2
• Node.js version: 6.13.4
• Operating System: XXX
• If TypeScript related: TypeScript version: XXX

Issue Template Checklist

How does this problem relate to dialects?

• I think this problem happens regardless of the dialect.
• I think this problem happens only for the following dialect(s):
• I don't know, I was using PUT-YOUR-DIALECT-HERE, with connector library version XXX and database version XXX

Would you be willing to resolve this issue by submitting a Pull Request?

• Yes, I have the time and I know how to start.
• Yes, I have the time but I don't know how to start, I would need guidance.
• No, I don't have the time, although I believe I could do it if I had the time...
• No, I don't have the time and I wouldn't even know how to start.

Note: I was able to come to this line which is merging the two orders. However, I think the community needs to collectively decide what should be the expected behaviour. I think that the order provided by findAll should always override the scope order.