Querying polymorphic relationship with [all] not working in payload 3

[Twansparant]

Describe the Bug

I'm currently in the process of migrating my Payload 2.28 project to Payload 3.14
In one of my field blocks, I have a Has Many - Polymorphic relationship field.

In Payload 2 I used to be able to run a query with multiple values (where the values can be either pages or products id's.) like this:

?where[polymorphic.value][all]=66e98b37e62a08c1d2caca54,66ed8d9e4e47342f77c96287

However running the exact same query in Payload 3 returns 0 docs.
My content has stayed the same (after running the mongo migration script)

Link to the code that reproduces this issue

https://github.com/Twansparant/payload

Reproduction Steps

1. Run reproduction code
2. Go the the example post in admin and select the example page & example product in the Polymorphic field.
3. Publish the changes
4. Lookup the ids for the example page & example product and replace them in the url of step 5
5. Go to url: http://localhost:3000/api/posts?where[polymorphic.value][all]=[example-page-id],[example-product-id]
6. The response has "totalDocs": 0 while it should have 1 containing the example post

Which area(s) are affected? (Select all that apply)

Not sure

Environment Info

Payload: v3.17.1
Node.js: v22.6.0
Next.js: v15.1.5

[Twansparant]

As addition, I also tried it with the qs-esm package like this:

import { stringify } from 'qs-esm'
import type { Where } from 'payload'

const query: Where = {
  'polymorphic.value': {
    all: '66e98b37e62a08c1d2caca54,66ed8d9e4e47342f77c96287',
  }
}

const getPosts = async () => {
  const stringifiedQuery = stringify(
    {
      where: query,
    },
    { addQueryPrefix: true },
  )

  const response = await fetch(`http://localhost:3000/api/posts${stringifiedQuery}`)
}

Resulting in the same response:

{
	"docs": [],
	"totalDocs": 0,
	"limit": 10,
	"totalPages": 1,
	"page": 1,
	"pagingCounter": 1,
	"hasPrevPage": false,
	"hasNextPage": false,
	"prevPage": null,
	"nextPage": null
}

At the moment, the only way to make it work, is by quering it with the AND and contains operators:

const query: Where = {
  and: [
    {
      'polymorphic.value': {
        contains: '66e98b37e62a08c1d2caca54'
      }
    },
    {
      'polymorphic.value': {
        contains: '66ed8d9e4e47342f77c96287'
      }
    }
  ]
}