RESOLVED: iOS Universal Link not working on second level subdomain

I have capabilities in my app that contain multiple applinks: entries like so:

    applinks:firstlevel.domain.com 
    applinks:second.level.domain.com

Universal links on the first level subdomain work fine and open the app. Universal links on the second level subdomain do NOT open the app (go to safari). My suspicion right now is because of the composite (2-piece) subdomain.

The apple-app-site-association files are completely identical on both, and are hosted and downloadable from both. Both URLs are hittable from our internal network and are on the same domain and TLD. SSL is configured correctly. There are no redirects taking place (verified through chrome dev tools)

Each respective apple-app-site-association file is hosted under appropriate subdomain (not on the root of domain.com). But the same top level domain is used for both subdomains in URL 1 and 2.

Can the second-level subdomain be the problem, or is it more likely that other network configuration differences are the problem? I couldn't find information online that states whether multiple subdomains are supported for universal links or not.

UPDATE: Tried removing the applinks:firstlevel.domain.com entry, to make sure the two subdomains aren't conflicting for the same bundle ID (and the site association). This did not make a difference. The second level subdomain still doesn't deep-link.

Any suggestions on how to diagnose why the second URL can not be opened as a deeplink in the app?

It's also not appropriate to use wildcards or upload the apple-app-site-association file to the root of the domain, because that's production, and should not have any lower environment settings on it.

Here's our apple-app-site-association file:

{

'webcredentials': {

'apps': ['ourteamid.ca.ourdomain.ourname']

},

'applinks': {

'apps': [],

'details': [{

'appID': 'ourteamid.com.ourdomain.ourname1.ourname2',

'paths': ['r/samplepath/*', 'en/r/samplepath/*', 'fr/r/samplepath/*']

}]

}

}