Large MKV video file sync fails in mobile with "corrupted file" after successful web upload

Description

Uploading a large .mkv video file via the web application succeeds (file appears, is downloadable), but when syncing the same project in the mobile app the sync fails with an error indicating the file is "corrupted." The failure blocks the sync.

Environment
Staging/PROD

Application (+ app version, build, operating system)

• Actual iOS app version: 2025.7.0 (25.10.815911)
• Actual iOS version: iOS 26.0

Steps to reproduce

1. In web app (PROD or Staging), open target project.
2. Upload a large .mkv video file (tried with: Máří Magdaléna (2018, CZ Dabing + CZ Forced).mkv).
3. On mobile app open the same project and start Sync.
4. Observe sync fails with a "corrupted_files" error referencing the uploaded .mkv. Sometimes is needed to repeat Sync to get this error.
5. Retrying sync produces the same error.

Actual results

• Sync aborts; mobile reports the newly uploaded .mkv as "corrupted." Other changes cannot be synced until resolved.
• this happens if file name is "Máří Magdaléna (2018, CZ Dabing + CZ Forced).mkv". If I rename it to "Maria-Magdalena.mkv" and upload it, sync is OK on mobile device
• user must delete .mkv file on dashboard and delete project from mobile app

Expected results

• Successful synchronization of large media files with the server

Screenshots or logs

Conclusion
Created by GitHub Copilot and supervised by a human test analyst.

Reproduce the sync failure on iOS using the reported large MKV filename, then compare it with the successful Maria-Magdalena.mkv upload. Trace the mobile sync handling for the uploaded file and use the observed error to identify why the filename or media file is reported as corrupted; done means the project syncs successfully without requiring a rename.