I’ve seen this problem going back to at least the 7.1.2 release. Running in AP mode (no wan), after configuring the SOHO to get time from a local router on the lan port, the SOHO never puts out a NTP request (verified by viewing the log file, and also doing a trace). I can sometimes get it working by doing a factory reset, and doing a manual configuration, but not consistently. Is there a way to figure out what is wrong without doing a reset and reconfig, which may or may not work?
I suggest you open a ticket with peplink support for this.