Saving and reopenning reorders content repeatable fields

I have created a subform set with a series of fields. The whole subform is repeatable.

example subform:

Title

1. Name

2. Description

3. Items (this is repeatable)

So users can fill out all the fields, then add another set (instance) of these fields with a button action.

Example:

Title 1

1. Dave

2. This is my first description

3. Green Item

    Blue Item

    Red Item

Title 2

1. Greg

2. This is my second description

3. Purple Item

    Yellow Item

This works great when filling out the form, but once it is saved and reopened, the order changes to this:

Title 1

1. Dave

2. This is my first description

3. Green Item

    Blue Item

    Red Item

    Purple Item

    Yellow Item

Title 2

1. Greg

2. This is my second description

3.

As you can see the repeatable items in the second subset (Purple Item and Yellow Item) move up to the first subset.

Any ideas why?