Message permanently not delivered in conjunction with Desktop app

Guidelines

• I have searched open and closed issues for duplicates
• I am submitting a bug report for existing functionality that does not work as intended
• This isn't a feature request or a discussion topic

Bug description

In the last months, I have repeatedly observed that certain messages are not being delivered to recipients (more than one recipient affected). The symptom is always the same, the message remains stuck with a single check mark. Later messages can arrive but that single check mark message remains stuck forever.

Today, I was able to reproduce this consistently with someone else, where all my message from the Desktop app would arrive immediately but messages sent from Android all went into single check mark mode and would never be delivered. It should be noted that I can see my own messages from Android on Desktop. I can't say for sure if in the past, it was always in this exact order (Desktop being received while Android messages not being received, or vice versa was also the case). I also tried closing the Desktop app now but new messages sent from Android are still getting stuck. After rebooting the Android phone, messages from Android are working again but the previously stuck messages remain stuck forever.

I understand that relinking everything might solve the problem (if the problem is related to the Desktop app at all, it could just be coincidence that one client stops working) but that would only paper over the underlying issue here which sounds like a serious bug that might actually be server-side given that the messages clearly left the phone and reached the server.

Screenshots

No response

Device

Vivo x300 Pro

Android version

Android 16

Signal version

8.23.3

Link to debug log

The debug log is available, happy to provide it directly to you

Start by obtaining the debug log mentioned in the report and reproduce the delivery failure with messages sent from Android while the Desktop app is linked. Compare the behavior before and after rebooting the Android phone, including whether previously stuck messages remain undelivered. Done means the cause is identified and affected messages are delivered reliably.