Conversation starts here: NTP issues on a dumb AP configuration - #13 by Cthulhu88
Does it match your setup (dumb AP-like)? If so, there seems to be a bug with sysntpd where it deadlocks, if it fails to resolve all of the hostnames on startup.
In that case, either delaying sysntpd enough or switching to raw IP addresses for NTP servers "fix" the issue.