Test Environment
OS: Windows_11
Version: 21H2
OS Build: 22000.795
Browser: Version 103.0.1264.71 (Official Build) (64-bit)
URL: data:text/html,%3cbutton%3eoutter%20target1%3c/button%3e%3cnav%20aria-labelledby=%22nav-1%22%3e%3ch2%20id=%22nav-1%22%3eTest%20navigation%3c/h2%3e%3cbutton%3einner%20target%3c/button%3e%3c/nav%3e

Repro Steps:

1. Visit this URL data:text/html,%3cbutton%3eoutter%20target1%3c/button%3e%3cnav%20aria-labelledby=%22nav-1%22%3e%3ch2%20id=%22nav-1%22%3eTest%20navigation%3c/h2%3e%3cbutton%3einner%20target%3c/button%3e%3c/nav%3e

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.