[PHP] Generated APIs incorrectly encode commas in certain query parameters

I have the same json definition but by different swagger-codegen have the deffirent in source code of API:

Version 2.4.8:

        if (is_array($filter_number)) {
            $filter_number = ObjectSerializer::serializeCollection($filter_number, 'csv', true);
        }
        if ($filter_item_number !== null) {
            $queryParams['filter[number]'] = ObjectSerializer::toQueryValue($filter_number);
        }

Version 2.4.9 and more:

        if (is_array($filter_number)) {
            $queryParams['filter[number]'] = $filter_number;
        }
        if ($filter_item_number !== null) {
            $queryParams['filter[number]'] = ObjectSerializer::toQueryValue($filter_number);
        }

Swagger Parameter: "collectionFormat: csv"

Description

The problem exist only for query params but it work correct for header params. (same functionality by version 2.4.8 and starting at 2.4.9)

Swagger-codegen version

starting at 2.4.9

Swagger declaration file content or url

...
        - name: 'filter[number]'
          in: query
          required: false
          items:
            type: string
          type: array
          collectionFormat: csv
          uniqueItems: true
...

Command line used for generation

unknown. It used from https://app.swaggerhub.com/
I can reproduce with: java -jar swagger-codegen-cli-2.4.12.jar generate -i the.json -l php -o /tmp/test

Start with the PHP generator output produced by swagger-codegen-cli-2.4.12.jar and inspect the query-parameter handling around ObjectSerializer::serializeCollection and ObjectSerializer::toQueryValue. Reproduce the issue using the supplied YAML shape and generation command, then compare query and header parameters. Done means CSV query values preserve the expected comma encoding behavior without regressing header parameters.