Lightroom Classic masking isn't accurately selecting the subject

I'm running Lightroom Classic v. 13.5 on a Mac Studio M2 Max under macOS Sonoma 14.6.1.

This issue did not exist for me in versions of Lightroom Classic prior to 13.4. Lightroom used to accurately select the subject, most of the time. In my case, the subject is almost always a person, sometimes more than one person. I often photograph people on the street, and I typically use Lightroom's masking to selectively apply edits to the subject(s) and to the background, separately.

I just upgraded to v 13.5, and I was hoping that this issue, which first appeared in v 13.4 for me, would be fixed, but the latest version's masking behavior is the same as the previous version: when I go to masking and click on Background, under Add New Mask:, Lightroom creates a mask that includes the Subject.

I have "Show Overlay" enabled, and my overlays have a translucent reddish color.

I've found a workaround for this. I click on the Subtract button and select the entire person (Subject) who I want to separate from the background. Then, Lightroom correctly applies a mask to the subject, and I can apply edits to the background.

But I shouldn't have to take these extra steps. Lightroom's masking of subjects and backgrounds was working much better for me in versions prior to v. 13.4.