Created attachment 355041 [details]
Reduced test case
Given the following markup:
<input id="checkbox-bar" name="foo" type="checkbox" value="bar">
<input id="checkbox-baz" name="foo" type="checkbox" value="baz">
Focus either checkbox.
This behaviour is also present in Safari Technology Preview release 70.
Voiceover should announce the label once, e.g.
"Foo, unticked, checkbox"
Voiceover announces the label twice, e.g.
"Foo, Foo, unticked, checkbox"
for some reason the <label> is being converted to a AXStaticText and it's reporting it has a child of its own (the actual static text item)
I can no longer reproduce this in Safari 14.0.2 (15610.3.7.1.10, 15610) on macOS 10.15.7 (19H114) – I think this has been fixed at some point.