iOS 7z archive verification issue with iCloud Drive

Environment

* App: Keka for iOS
* Version: v1.6.6 (1715)
* iOS: iOS 26.6

Description

I found an issue with archive integrity verification in Keka for iOS.

A password-protected 7z archive can be opened, browsed, and extracted successfully after being stored in iCloud Drive. However, the “Test archive / Verify integrity” function fails or does not work correctly after the archive has gone through iCloud Drive.

The same archive works correctly when stored locally on the device.

Steps to reproduce

1. Create or copy a password-protected 7z archive.
2. Store the archive locally on the iOS device.
3. Open it with Keka and run archive integrity verification.
* Result: Verification works normally.
4. Upload the same archive to iCloud Drive.
5. Open the archive from iCloud Drive (or copy it back to local storage).
6. Run archive integrity verification again.
* Result: Verification fails / does not complete correctly.

Expected behavior

The integrity verification should return the same result regardless of whether the archive is stored locally or accessed through iCloud Drive.

Actual behavior

* Archive browsing works normally.
* Password entry works normally.
* Full extraction works successfully.
* Only archive integrity verification is affected.

Additional information

The issue appears to be related specifically to the verification process rather than archive data corruption, because:

* The archive contents can be viewed.
* The archive can be fully extracted without errors.
* The same archive verifies correctly when stored locally.

Possible relation:

* iOS iCloud Drive file provider behavior
* Random/sequential file access differences during verification
* File coordination or cached file handling

Thank you for maintaining Keka for iOS. Let me know if additional test files or logs are needed.