Subject mask crashes Lightroom on iphone

Experiencing the same issue on Desktop after recent update

Hi josep32207180. Welcome to the Lightroom Community. I'll help you figure this out. 

We need some info to help you. Would you mind sharing the video recording of what exactly happening when you select Subject Mask? 

Also share Lightroom logs with us by following these steps: 

1. Launch the Lightroom app and tap the setting icon in the upper-right corner.

2. From Lightroom settings, select Help & Support.

3. Press and hold Access our Support Forum.

4. Tap Create in the App Diagnostics dialog box.

5. Lightroom will start generating the logs.

6. Once generated successfully, the diagnostic logs will be attached to the mail. You can then share the logs.

You can take help from this link for the steps to generate Lightroom logs: https://helpx.adobe.com/lightroom-cc/kb/generate-share-logs-lightroom-mobile.html.

Please check this discussion here our Community Experts has provided solution for this issue you may find solution here: https://community.adobe.com/t5/lightroom-ecosystem-cloud-based-discussions/select-subject-sky-crashes/m-p/13349742.

Let me know if this helps. 

Thanks! 

Shivani