You are implementing NAP in Reporting mode. You may face a problem with retrieving Windows System Health Validator Results that NPS Event Log contain empty string in Windows Security Health Validator details section.
Well, normally WSHV section should contain information about nap client validation results either for full or quarantine access.
This is an known issue when the locale on NPS is not English.
On NPS, set the locale to English:
1. Log on to an account with administrator privileges.
2. Click the Start button, point to Settings, click Control Panel, and then double-click Regional Settings.
3. Click the Regional Settings tab.
4. Click US locale.
5. Click Set As System Default Locale, so that it is selected, and then click OK.
6. Restart your computer to activate the selected system locale.