Default value referencing another field from the same form not applied when adding a new feature

[RastoHu]

Description

When a form field has a default value expression that references another field from the same form (e.g. "project" || ' ' || "date"), the default value is not applied when adding a new feature under specific conditions. The default value is correctly applied when editing/updating an existing feature.

Environment
[x] Staging [ ] PROD

Application (+ app version, build, operating system)

• Mergin Maps mobile 2026.1.2
• iOS 26.0

Steps to reproduce

1. In QGIS, open an existing Mergin Maps project or create a new one via the Mergin Maps plugin
2. Create a new GeoPackage file with at least 3 fields, project (text), date (date/time), and name (text). Set default value expressions: project → @mm_project_name, date → now()
3. In the field properties for name, set the default value expression to "project" || ' ' || "date" and enable Apply default value on update
4. Sync the project to Mergin Maps
5. Open the project in the Mergin Maps mobile app
6. Start adding a new feature — verify that the name field is correctly populated with the default value (no manual input needed, all values are filled by default expressions) — then cancel without saving
7. Start adding another new feature at the same location (without moving the map canvas)

Actual results

• The name field remains NULL after saving the new feature
• The name field is correctly populated after subsequently editing/updating the same feature

Expected results

The name field should be populated with the concatenated value of project and date (e.g. MyProject 2024-03-24) already when adding the new feature.

Screenshots or logs

ScreenRecording_03-24-2026.13-03-57_1.MP4

Conclusion
Created by Claude and supervised by a human test analyst.