Exposure Adjustment Reverts When Switching from Smart Preview to Original with GPU Acceleration Enabled (Lightroom Classic 15.2)

Product

Adobe Lightroom Classic
Version: 15.2
OS: Windows 11
Camera RAW Format: Canon CR3
GPU: NVIDIA GeForce RTX 3050 Laptop GPU (4GB)
Graphics Processor Setting: Custom

• GPU for image processing: Enabled

• GPU for export: Enabled

• GPU for preview generation: On

• Full graphics acceleration enabled

Summary

When “Use Smart Previews instead of Originals for image editing” is enabled, exposure adjustments made before the full-resolution original is loaded are reverted once the original file loads (triggered by zooming to 100% or any other zoom).

Both the Exposure slider value and the visual rendering reset to their previous state.

This issue is 100% reproducible under the configuration described above.

Expected Behavior

• Develop adjustments applied while editing via Smart Previews should persist.

• Switching from Smart Preview to the full-resolution RAW should not override committed develop parameters.

• Slider state and render output should remain consistent across rendering pipeline transitions.

Actual Behavior

1. Exposure is adjusted while the image is still rendered from Smart Preview.

2. Adjustment appears correctly applied.

3. Zooming to 100% triggers loading of the original CR3 file.

4. Upon re-render:

   • The Exposure slider resets to its previous value.

   • The visual exposure adjustment is reverted.

5. Navigating away and back confirms the change was not committed.

Impact

• Silent loss of edits

• Breaks non-destructive editing trust

• Forces users to wait for full-resolution load before adjusting exposure

• Impacts workflow efficiency in high-volume editing scenarios