What's happening
User select files in UploadWizard and complete every steps. On the last step, while uploads are finalized, somes files are succesful but then we see a message saying "You must be logged in to upload this file.". Opening a new page indeed show we are logged out.
Logging In again and retrying may result in the same behavior when pressing "Retry failed upload".
The session is not expired or timed out when uploading, I tried with a fresh new session and another browser.
Because of this issue I now upload in batch of ~200, and after 100 files or so the session "expires".
An IRC user suggested I open an issue in case someone else eventually face the same issue. I hope I provided enough information.
Versions
MediaWiki 1.32.0
PHP 7.2.15 (fpm-fcgi)
APCU 5.1.17
MariaDB 10.3.12-MariaDB
ICU 50.1.2
Upload Wizard 1.5.0
https://gamewiki.kuelio.org/Special:Version (Information on this page is subject to change)