Adobe Commerce Marketplace Error: “Repo rejected file upload – Failed” despite correct ZIP structure and version bump

I am trying to publish an update for our official module (Oct8ne) on the Adobe Commerce Marketplace, but the automated validation keeps failing instantly with this generic error:

“Repo rejected file upload – Failed”

We are updating the module to version 1.7.5. I have already contacted Adobe Support, but they only provide a generic checklist. I have strictly followed all their documentation and guidelines, but the error persists.

Here is everything we have already checked and fixed:

• Naming Convention: The ZIP file is named exactly oct8ne_oct8ne-1.7.5.zip (matching the vendor_package-version.zip requirement).
• Version Conflict: We bumped the version to 1.7.5 in both composer.json and etc/module.xml. This version has never been uploaded before, so it shouldn’t be hitting a cache/already-exists conflict.
• Package Structure: The ZIP was compressed directly from the files. There are no root wrapper folders, and all hidden OS files (.DS_Store, __MACOSX) have been stripped.
• Composer Setup: The name is explicitly set to "oct8ne/oct8ne".

Here is a simplified version of our composer.json:

{
    "name": "oct8ne/oct8ne",
    "description": "Oct8ne official connector for Magento 2",
    "type": "magento2-module",
    "version": "1.7.5",
    "require": {
        "php": "~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0 || ~8.5.0",
        "magento/framework": "~103.0.0"
    },
    "autoload": {
        "files": [
            "registration.php"
        ],
        "psr-4": {
            "Oct8ne\Oct8ne\": ""
        }
    }
}

Has anyone else experienced this exact issue recently? Are there any hidden validation rules regarding the composer.json or ZIP structure that are not clearly documented?

Any guidance on how to bypass this or force the Marketplace to show the actual validation log would be greatly appreciated.