I forgot to reply my own post. I find the issue and the resolution. I post it if anyone ever has the same problem.
Actually, I was using a re-order plugin on the post-type I tried to query, called Post-Types-Order.
This plugin seems to automaticaly apply a filter for all queries that are pointed the re-ordered post-type. Even in your own code.
There’s a way to prevent that in the API, by adding a parameter in the query args :
ignore_custom_sort' => true
You can find an example here : https://www.nsp-code.com/advanced-post-types-order-api/sample-usage/ (Don’t need to get advanced version to use it).
