Issue Summary

When adding an image as an attachment parameter to the Chart macro and saving the page, Confluence throws a system error. The following exception is logged on the server:

2026-02-19 09:10:08,544 ERROR [http-nio-8090-exec-49 url: /confluence/spaces/TEST/pages/163935/Chart+macro, /confluence/pages/viewpage.action; user: admin] [xhtml.view.macro.ViewMacroMarshaller] handleMacroExecutionException Error rendering macro: chart
 -- page: 163935 | referer: https://linux-120497.prod.atl-cd.net/confluence/pages/editpage.action?pageId=163935 | traceId: 079784cf0a4d6ded | userName: admin | action: viewpage | url: /confluence/spaces/TEST/pages/163935/Chart+macro
org.hibernate.NonUniqueObjectException: A different object with the same identifier value was already associated with the session : [com.atlassian.confluence.pages.Page#163935]
	at org.hibernate.engine.internal.StatefulPersistenceContext.checkUniqueness(StatefulPersistenceContext.java:700)
. 

Issue Demo:

chart-macro_error.mp4

The issue is observed in 10.x version. The Confluence 9.2.x version is working fine. 

Steps to Reproduce

1. Edit an existing page (e.g. /confluence/pages/editpage.action?pageId=163935) or create a new page.

1. Insert a Chart macro into the page.

1. Configure the Chart macro to use an image stored as a page attachment as one of its parameters (e.g., select an attached image file in the macro configuration).

1. Save the page.

Expected Results

• The page saves successfully.

• The Chart macro renders without errors while using the image attachment parameter.

Actual Results

• A system error occurs after saving the page.

• Viewing the page throws the same error.

Workaround

Remove the attachment from the chart parameter and save the page.