I am experiencing a display issue in InDesign 2026 when using Overprint Preview or Separations Preview.

CMYK objects placed on the pasteboard (outside the page) become significantly darker, while the same objects displayed inside the page remain correct.

The same document does not show this issue in InDesign 2025.

I have tested this issue in multiple versions of InDesign 2026:

Version 21.4.1.4
Version 21.5.1

The same issue occurs in both versions.

Environment
Adobe InDesign 2026
Versions tested: 21.4.1.4 and 21.5.1
Mac mini M4 Pro
macOS Tahoe 26.6.2 (25G83)
Monitor: EIZO ColorEdge CX240
Connection: USB-C to DisplayPort
Issue

I have CMYK text and graphic objects positioned so that they extend from the page area onto the pasteboard.

In Normal Preview, everything displays correctly both inside the page and on the pasteboard.

However, when print simulation preview modes are enabled, the objects on the pasteboard display incorrectly.

When Overprint Preview is enabled

When I enable:

View > Overprint Preview

the display changes as follows:

CMYK objects inside the page → display correctly
The same CMYK objects on the pasteboard → become significantly darker
Placed photos on the pasteboard → may disappear

The CMYK values of the objects are the same.

The appearance changes specifically when the object crosses from the page area onto the pasteboard.

Separations Preview test

I also tested:

Window > Output > Separations Preview

Preview: Off
Inside page → Correct
Pasteboard → Correct
Preview: Separations
Inside page → Correct
Pasteboard → CMYK objects become significantly darker
The same issue occurs as with Overprint Preview

Therefore, the problem also occurs when Separations Preview is set to Separations.

Both Overprint Preview and Separations Preview produce the same incorrect display behavior on the pasteboard.

Summary of test results
Preview mode Inside page Pasteboard
Normal Preview Correct Correct
Separations Preview: Off Correct Correct
Overprint Preview Correct CMYK becomes darker / images may display incorrectly
Separations Preview: Separations Correct CMYK becomes darker / same issue
Comparison with InDesign 2025

I tested the same document in InDesign 2025.

With Overprint Preview enabled, objects display correctly both inside the page and on the pasteboard.

However, the issue occurs in InDesign 2026.

I tested:

Version 21.4.1.4
Version 21.5.1

and the same issue occurs in both versions.

This appears to be a possible display regression or rendering issue introduced in InDesign 2026.

Steps to reproduce
Create a new document
Create a text or graphic object with a CMYK fill
Position the object so that it extends from the page onto the pasteboard

Enable either:

View > Overprint Preview

or

Window > Output > Separations Preview > Preview: Separations
Compare the appearance of the object inside the page and on the pasteboard

The CMYK object displays correctly inside the page but significantly darker on the pasteboard.

Expected result

The same CMYK object should display consistently and correctly both inside the page and on the pasteboard when Overprint Preview or Separations Preview is enabled.

At minimum, I would expect the same behavior as InDesign 2025.

I would appreciate it if others could test whether this issue can be reproduced on other systems, or confirm whether there has been an intentional change to pasteboard rendering in InDesign 2026.

Screenshots are attached.