Continuous reload loop when editing a Nextcloud-hosted PDF in PDF Expert

AI DIsclosure: this bug report was created with assistance from ChatGPT Instant 5.5
Environment*

• Device: iPad Pro 11-inch M4, model MVW33KN/A
• iPadOS: 25.5.2
• Nextcloud iOS: 34.1.1.2
• Nextcloud Server: 32.0.13
• PDF Expert: 7.25.10

Problem

When a PDF stored in Nextcloud is opened in PDF Expert, adding even one short pen annotation causes the document to enter a continuous reload or rendering loop.

Approximately every 1–2 seconds, the displayed page changes from the sharp rendered version back to a blurry preview and then becomes sharp again. At the same time, PDF Expert’s menus and toolbars disappear, making the document very difficult to use.

The behaviour continues indefinitely even when the iPad is no longer being touched.

Some PDFs begin flashing immediately when opened, but for most tested documents it begins as soon as the first pen annotation is added.

Steps to reproduce

1. Store a PDF in Nextcloud.
2. Ensure that it is downloaded and available locally on the iPad.
3. Open it in PDF Expert.
4. Draw one short line using PDF Expert’s pen tool.
5. Stop interacting with the document.

Observed result

The document repeatedly switches between a blurry preview and the fully rendered page every 1–2 seconds. PDF Expert’s toolbar disappears during each refresh.

Expected result

The annotation should be saved without causing the document to reload repeatedly.

Additional observations

• The problem occurs both when the PDF is opened through the Nextcloud Files provider and when Nextcloud is accessed from within PDF Expert.
• Copying the identical PDF to “On My iPad” eliminates the problem.
• Opening and editing the identical PDF from iCloud Drive does not produce the problem.
• The PDF displays normally in Nextcloud’s own viewer.
• Making the Nextcloud file available offline does not prevent the problem.
• Disconnecting the iPad from the network stops the flashing, but PDF Expert then freezes.
• Restarting the iPad and updating PDF Expert did not help.

This appears to be a repeated save/change-notification loop between PDF Expert and Nextcloud synchronisation.

Start by reproducing the loop with the listed Nextcloud, iPadOS, and PDF Expert versions, comparing the Files provider, PDF Expert integration, offline mode, and network-disabled behavior. Done means a pen annotation saves without repeated blurry-preview reloads, toolbar disappearance, or freezing.