Guided Upright Update shouldn't ignore Leica Perspective Control metadata

Description of Issue
On Leica DNG files, Transform > Upright > Guided correctly applies the camera-embedded Perspective Control (LPC) guide lines the first time, as long as the photo has not been edited yet. Clicking Update (“Aktualisieren”) after that does not re-apply the embedded Leica guides. The LPC correction is lost or cannot be recalculated.

This is specific to Leica Perspective Control metadata. Manual Guided lines are a different workflow.

Lightroom Classic Version Number
15.5 (Help > System Info)

OS Version Number
macOS 26.6.1

Camera Model
Leica M11 and SL3 ,  original in-camera DNG (not “Copy as DNG”, not “Render to DNG”)

Step-by-step Reproduction Instructions
1. Import an unedited original Leica DNG that contains Perspective Control / LPC metadata.
2. Open Develop > Transform.
3. Click Upright > Guided (“Mit Hilfslinien”).
4. Observe that the Leica-embedded guides are applied and the perspective correction works.
5. Click Update (“Aktualisieren”) in the Upright panel.
6. Optionally click Guided again.

Expected Result
Update should re-apply or refresh the Leica-embedded LPC guides from the DNG metadata, same as the first Guided click on an untouched file.

Actual Result
The first Guided click on an untouched file works. After Update, the embedded Leica guides are not applied again. I must not click Update, or the LPC correction breaks.

Workaround
Do not click Update. Only use Guided once on an unedited file. If Update was clicked, Reset the Transform panel and start over, or draw guides manually.