WebSocket connection instantly closes (FIN) on iPadOS 26 in PWA (Local HTTP/WS)

I am maintaining a PWA that utilizes WebSockets. In this app, after the web page is loaded from the server, JavaScript establishes a WebSocket connection.

Because the app connects to a completely local server on a managed local network, we use http:// and ws:// (non-secure).

The Issue: The app worked perfectly from older iOS versions up to iPadOS 18. However, during testing on iPadOS 26, we encountered an issue where the WebSocket connects successfully but is disconnected by the iPad approximately one second later.

According to our packet captures, the iPad is sending a FIN packet to initiate the teardown.

Additional Context: What makes this particularly confusing is that we have another server hosting the exact same PWA where the WebSocket connection stays stable even on iPadOS 26. This suggests it might not be a universal OS bug, but perhaps related to specific network conditions or a new security policy.

Has anyone experienced similar behavior on iPadOS 26?

Could this be a bug, or is there a new security restriction regarding non-secure WebSocket (ws://) connections in local networks?

Are there any known changes in WebKit/Safari for iPadOS 26 that might cause the OS to send a FIN packet immediately after a handshake?

I would appreciate any insights or suggestions on what might be causing this.

Our engineering teams need to investigate this issue, as resolution may involve changes to Apple's software. Please file a bug report, include a small Xcode project and some directions that can be used to reproduce the problem, and post the Feedback number here once you do. If you post the Feedback number here I'll check the status next time I do a sweep of forums posts where I've suggested bug reports.

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WebSocket connection instantly closes (FIN) on iPadOS 26 in PWA (Local HTTP/WS)
 
 
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