Mysterious crawl-to-a-halt, not passing packets (SFP interface)

[Koloa]

This is not likely something that anyone will be able to assist with, as I've got VERY little to go on, but, I thought I'd share it anyway.

Earlier this morning, whilst I was in the midst of doing a software update on a phone, the phone stopped getting packets - so I checked my OPNsense router and, well, I couldn't.  It wasn't responding to the web GUI or to the SSH interface.  ICMP was also mostly failing, but, in testing over a few hours sometimes I'd get a 3000+ms response.

The only log entries from the time are:

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2025-12-04T06:07:12Noticekernel [432226] ax0: xgbe_phy_sfp_signals: port_sfp_inputs: 0x0
2025-12-04T06:07:12Noticekernel <7>[508295] sonewconn: pcb 0xfffff80294736540 ([::]:53 (proto 6)): Listen queue overflow: 193 already in queue awaiting acceptance (1 occurrences), euid 0, rgid 0, jail 0
2025-12-04T06:08:54Noticekernel <7>[508397] sonewconn: pcb 0xfffff80294736540 ([::]:53 (proto 6)): Listen queue overflow: 193 already in queue awaiting acceptance (131 occurrences), euid 0, rgid 0, jail 0

And that's it.  Nothing else in the log at all around the time it happened.

Unfortunately, I was heading out the door, and didn't get to look at it again till around 1030 (4.5 hours later).

And, as luck would have it, literally ALL I did was look at my router (Dec750), then go to my desk and try to ssh in and it was fine.

Web GUI worked too.

Out of an abundance of caution, I did reboot the device, and everything seems normal since that time.

During the 4.5 hours I wasn't near the box, I did repeatedly try to ping it from other devices on the network whilst I was out, and that's when the 3000+ms response times were noted (mostly no response at all).

For the moment, I'm chalking this up to "bad electrons" via the SFP, but, if the above three lines help anyone else say "aha!" I'd appreciate knowing.

Thanks!

P.S.  OPNsense 25.7.8-amd64 / FreeBSD 14.3-RELEASE-p5