This article describes and explains an issue where the gui-waf-profile setting that is enabled on the System -> Feature Visibility page will be lost or disabled after an upgrade or reboot.
Scope
FortiGate.
Solution
The following logs are generated after a reboot or upgrade.
diagnose debug config-error-log read "set" "gui-waf-profile" "enable" @ root.system.settings:value parse error (error -1)
However, this should be a cosmetic issue only since the WAF profile can still be seen applied in the intended Firewall Policies.
This known issue was resolved in the FortiOS release 7.4.1 and will be resolved in the upcoming FortiOS releases 7.2.10, 7.4.5, and 7.6.0.