[BUG] Offline Photos/Videos Not Syncing Correctly

Actual behaviour

-Observing issues trying to save a folder offline with various photos and videos in them
-It seems local eTag of these photos, for example, can be just "" and the localModificationTimestamp is more recent. Even though the picture may just have been opened, but not actually modified. This triggers reuploads/redownloads when syncing.

Expected behaviour

-All photos/videos on the server should download successfully and not re-upload any old photos.

Steps to reproduce

1. Place a collection of photos and videos on the server in one folder
2. Set folder offline
3. Observe synchronization/downloading conflicts
4. Observe a fileToSynchronize where eTag is "" and localModificationTimestamp is recent, which triggers changedLocally and changedRemotely in SynchronizeFileUseCase.kt

Can this problem be reproduced with the official owncloud server?
(url: https://ocis.ocis.master.owncloud.works, user: einstein, password: relativity)

Environment data

Android version:
16
Device model:
Pixel 10
Stock or customized system:
Stock
ownCloud app version:
4.7.0
ownCloud server version:
10.18.0

Logs

Web server error log

Not seeing a lot of logs regarding this file from today:

192.168.1.5 - alex [15/Nov/2025:12:22:49 +0000] "PROPFIND /remote.php/dav/files/alex/Photos/Photos%20from%202025/PXL_20251109_043929876.mp4 HTTP/1.1" 207 1724 "-" "Mozilla/5.0 (Android) ownCloud-android/4.6.2"
192.168.1.5 - alex [15/Nov/2025:12:23:08 +0000] "PROPFIND /remote.php/dav/files/alex/Photos/Photos%20from%202025/PXL_20251109_043929876.mp4 HTTP/1.1" 207 1724 "-" "Mozilla/5.0 (Android) ownCloud-android/4.6.2"
192.168.1.5 - alex [15/Nov/2025:12:23:11 +0000] "PROPFIND /remote.php/dav/files/alex/Photos/Photos%20from%202025/PXL_20251105_195209298.mp4 HTTP/1.1" 207 1724 "-" "Mozilla/5.0 (Android) ownCloud-android/4.6.2"

ownCloud log (data/owncloud.log)

192.168.1.5 - alex [15/Nov/2025:12:22:49 +0000] "PROPFIND /remote.php/dav/files/alex/Photos/Photos%20from%202025/PXL_20251109_043929876.mp4 HTTP/1.1" 207 1724 "-" "Mozilla/5.0 (Android) ownCloud-android/4.6.2"
192.168.1.5 - alex [15/Nov/2025:12:23:08 +0000] "PROPFIND /remote.php/dav/files/alex/Photos/Photos%20from%202025/PXL_20251109_043929876.mp4 HTTP/1.1" 207 1724 "-" "Mozilla/5.0 (Android) ownCloud-android/4.6.2"
192.168.1.5 - alex [15/Nov/2025:12:23:11 +0000] "PROPFIND /remote.php/dav/files/alex/Photos/Photos%20from%202025/PXL_20251105_195209298.mp4 HTTP/1.1" 207 1724 "-" "Mozilla/5.0 (Android) ownCloud-android/4.6.2"

The reported entry point is SynchronizeFileUseCase.kt; start there by tracing how an empty eTag and recent localModificationTimestamp produce changedLocally and changedRemotely during offline-folder sync. Reproduce with a folder containing photos and videos, using the listed ownCloud server if available. Done means server files download successfully without old photos being re-uploaded or repeated conflicts.