Photoshop 27.11 – Flickering when painting on adjustment layer masks with the new Light adjustment

Product: Adobe Photoshop Desktop
Version: 27.11
Operating system: macOS Sequoia
Computer: MacBook Pro 15-inch (2019)
Processor: Intel Core i7, 6 cores, 2.6 GHz
Graphics: AMD Radeon Pro 555X
RAM: 16 GB

Description of the issue

When painting on the layer mask of a Curves adjustment layer, the image and adjustment previews flicker if a newer Light adjustment layer is enabled above it in the Layers panel.

The issue occurs in a document containing grouped adjustment layers. It makes it difficult to see the image accurately while painting on the mask.

Layer structure

The issue can be reproduced with the following layer structure:

• Light group

  • Light adjustment layer with a white mask (Brightness/Contrast or the newer Light adjustment, depending on the setup).

  • Skin Light group, with a mask affecting only the model's skin.

    • Curves adjustment layer named “+ Light”, with a black mask.

    • Curves adjustment layer named “- Light”, with a black mask.

Steps to reproduce

1. Open a Photoshop document containing the layer structure described above.

2. Enable the newer Light adjustment layer above the Skin Light group.

3. Select the mask of the “+ Light” Curves adjustment layer.

4. Paint on the mask using the Brush tool.

5. Observe the image and adjustment previews.

Expected result

The image and adjustment previews should remain stable while painting on the Curves layer mask.

Actual result

The image and adjustment previews flicker while painting on the mask, making it difficult to work accurately.

Workaround confirmed

Changing the Light adjustment's processing mode from “Latest” to “Legacy 2026” eliminates the flickering on my system.

Re-enabling the newer “Latest” mode causes the issue to return.

This strongly suggests that the problem is related to the processing or compositing of the newer Light adjustment when painting on masks of underlying adjustment layers.

Additional information

• The issue is reproducible with the same document and layer structure.

• Disabling the Light adjustment layer also stops the flickering.

• Disabling GPU acceleration did not resolve the issue.

• Photoshop's allocated RAM is 8,770 MB, within the recommended range displayed by the application.

Please investigate whether this is a regression in the newer Light adjustment processing introduced in Photoshop 27.10 or affecting Photoshop 27.11, particularly when used above grouped Curves adjustment layers with masks.

Thank you.