Hi
I think the issue is not with mendix but architectural decisions.
When you duplicated only some pages, Mendix validates everything that becomes reachable from the offilne navigation profile So you need to double check everything like snippets, layouts some nanoflows, and entities.
The shared pages, layouts, snippets, and navigation actions can pull more of your existing phone web model into the offline validation scope.
I'll attach some documents hope they help
https://docs.mendix.com/refguide/mobile/building-efficient-mobile-apps/offlinefirst-data/synchronization/
https://docs.mendix.com/refguide/mobile/introduction-to-mobile-technologies/progressive-web-app/
Hi Duha Hamwi
The thing which you are currently is a issue when you mix two concepts wrongly .Once an entity is marked for offline sync, Mendix enforces offline-compatible rules across all profiles for any page/widget that uses that entity even in your online Phone Web profile. The entity's sync configuration is global, not profile-scoped, Any widget or action bound to an offline-synced entity must use nanoflows. This bleeds into your online profile if the same entity is referenced there.File upload is not supported in offline profiles. The File Dropper widget and After Commit microflows on entities will always fail offline validation.
The solution is to create a dedicated domain model subset and avoid marking shared production entities as offline-sync. if ypu are planning to use the same then in that case the sync concept should be developed using custom logic instead of mendix default. I hope this helps, If you have more question , I am happy to help