Note attachments not syncing between desktop clients

Operating system

macOS

Joplin version

3.4.12

Desktop version info

macOS:
Joplin 3.4.12 (prod, darwin)

Device: darwin, Apple M2
Client ID: 3ebfd8bc5d5b47cea1d91cdfea39c6f8
Sync Version: 3
Profile Version: 48
Keychain Supported: Yes
Alternative instance ID: -

Revision: e9a9f68

Backup: 1.4.3
Freehand Drawing: 3.1.0

Arch:
Joplin 3.4.12 (prod, linux)

Device: linux, Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz
Client ID: b7524720f6df4cb4862d24314ec73619
Sync Version: 3
Profile Version: 48
Keychain Supported: No
Alternative instance ID: -

Backup: 1.5.1
Freehand Drawing: 4.2.0

Pop_OS!
Joplin 3.4.12 (prod, linux)

Device: linux, Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz
Client ID: f0ffcf3c59ea41159ecff2b43c60fba7
Sync Version: 3
Profile Version: 48
Keychain Supported: No
Alternative instance ID: -

Backup: 1.5.1
Freehand Drawing: 4.2.0

iOS:
Client ID: 83900d257ac045efb465c9f577bd70f5
Sync Version: 3
Profile Version: 48
Keychain Supported: No
Alternative instance ID: -

Revision: cff96b130 (release-3.4)

iOS version: 26.1
FTS enabled: 1
Hermes enabled: 1

Sync target

Joplin Server

Editor

Markdown Editor

What issue do you have?

I have been using Joplin for over a year now and love it. I have been hosting it myself on a Raspberry Pi, using the provided Docker image. All was running great, but I noticed that attachments aren't syncing properly between desktop devices.

If I attach an image to a note on my desktop device, it will sync to my mobile device with no problem.

If I attach an image to a note on my mobile device, it will not sync to my desktop device. The notes themselves synch properly between devices, but attachments from the mobile device do not sync to dektop. I see the reference to the attachment on the desktop, but the attachment does not render.

Similarly, attachments don't synchronize between desktop devices. Only mobile devices see all attachments from all notes regardless of where they were created. Again, the notes themselves sync, it's just the attachments that aren't synching properly.

Since the notes themselves sync, I can't say for certain when this started. I just now noticed it. I set up a fresh installation of Joplin server on TrueNAS to verify that this isn't specific to my existing setup, notes, or encryption. The symptoms remain on a fresh Joplin server with no encryption.

I am using the latest server version from Docker Hub (3.5.2) as well as the latest dekstop clients (3.4.12) for macOS, the Flathub version for Arch, the Pop_Shop! version for Pop_OS, and the latest App Store version (13.4.4) for iPhone and iPad.

I am new to Joplin, so I wanted to raise this here before creating a GitHub issue since it might be a config error on my part. Any help is appreciated. Thank you!

Screenshots

I committed the grave sin of testing in-situ and not testing in isolation from my infrastructure. When installing Joplin server on a fresh server on my local network and connecting with the same clients, everything worked perfectly with all notes and images synching between all devices.

Working backwards from there and scrutinizing my network setup, it seems that Anubis was causing the problem. I had forgotten to consider Joplin when I had set it up on my domain. Exempting Joplin from the proxy through Anubis solved the problem.