IOS 18 Safari on Mobile data network not uploading files

Hello,

I am facing a strange issue on iOS 18. After upgrading to iOS 18, I noticed the following problem:

When connected to mobile data (with Wi-Fi turned off) and trying to upload a file larger than 1MB, the connection times out. However, if I repeat the same action using Wi-Fi, everything works fine.

I have tested this issue in various ways, but nothing seems to resolve it. It appears that iOS 18 might have introduced a bug.

You can replicate the issue using this site: https://video.online-convert.com/convert-to-mp4 (Note: this is not my page, but I found the same issue here).

From the server access logs, I see successful pre-flight requests, but the main POST request never follows, which suggests that the client is not sending the request.

I am no longer able to replicate this issue after upgrading to iOS 18.2 (released on Dec 11)

Multiple customers are experiencing this as well, which is a bummer.

The issue seems to be fixed in 18.2 although Apple didn't announce it along with 18.2 release. Enable experimental network loader is now "truly" OFF in 18.2 @hbhalodia @AlexPolt @toddpgoodall @peterlockhart

IOS 18 Safari on Mobile data network not uploading files
 
 
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