hAP ax S - Routing breaking

We are having major issues with the Mikrotik hAP ax S, this has been ongoing since we first deployed them and had hoped we'd had seen a fix by now.

My question - is anyone else noticing issues where the ax S stops routing properly and requires a reboot to correct? Symptoms aren't always the same, but in most cases for us you can ping the internet, PPPoE doesn't drop, but anything above say 500 MTU won't work. You can't Winbox in most of the time and according to some of our customers, you can't connect new devices to the WiFi.
For our worst cases, this happens multiple times a day until the router is rebooted, but if you replace the router with an ax2 or ac3 with the exact same config the issues stop happening.

For most of our connections either this doesn't happen very often, or at all, but our worst offenders seem to have the same things in common:

  • Have a CAP or another type of AP
  • Have a Cambium 4500 sector with 4525L CPE

Fibre connections or Ubiquiti wireless connections don't seem to be affected, or it happens far less often.
We've tried every ROS version since we first noticed the issue when we first raised it with Mikrotik (7.21.4) including the latest.

Sometimes if you leave it long enough it will fully crash and reboot itself and state "router was rebooted without proper shutdown, probably kernel failure" but most of the time it requires a power cycle.

Very curious if anyone else out there has experienced similar issues with this model router.

Yes. There's a recall on some serial numbers. AX S Manufacturing Issue? - #49 by jackrabbit

Hi,
Just for the record :slight_smile: — I set up a single unit of this model as the main router, but after a few spontaneous reboots over the course of eight months—plus a hack involving a "busybox" file—it died. I’ve sent it to the supplier/vendor for servicing to determine exactly what happened. I’m waiting for feedback from the service center (and I’ll share it if I get any). It’s a fantastic solution for a small office, but based on my experience with this single unit, I can't really classify it definitively.
Regards,,,

Unfortunately Mikrotik hasn't responded to my ticket despite multiple updates so I am unsure if this is at all related, most of our routers have a serial starting with HK.

A bit of a further update, after monitoring a few more closely it seems to be a combination of any type of AP and Cambium 4525L CPE.