regions labeled by aria-labelledby won't read with NVDA. #13307

Steps to reproduce:

1. visit this URL.

   data:text/html,<button>outter target1</button><nav aria-labelledby="nav-1"><h2 id="nav-1">Test navigation</h2><button>inner target</button></nav>
   

2. Hit the b key to focus the button in the region. arrowing also works but the button skips the header.
3. Observe what NVDA syas.
4. use object navigation to escape the region.

Actual behavior:

Upon entering, nvda does not read the labelledby but it does read the labelledby when I touch the node with object nav.

Expected behavior:

The heading is read

System configuration

NVDA installed/portable/running from source:

installed

NVDA version:

alpha-24583,61000de2

Windows version:

Windows 11 21H2 (x64) build 22000.434

Name and version of other software in use when reproducing the issue:

Chrome: Version 97.0.4692.99 (Official Build) (64-bit)
Issue also repros under firefox, so rendering engine independent.