HA + Zigbee2MQTT + HomeKit all stop responding, but Docker host still answers ping

I’m using a Jetson Nano as a small always-on home server. I run Home Assistant, Zigbee2MQTT, and my other services entirely in Docker.

Every ~2–3 days, the system becomes partially unresponsive. I usually notice because my Home Assistant lights stop working from my phone and HomeKit also stops responding.

The weird part is that the Jetson doesn’t appear to completely disappear from the network.

When it’s in this state:
ping 192.168.4.33 works normally with ~3–4 ms latency and 0% packet loss
TCP port 22 is reachable
TCP port 8123 (Home Assistant) is reachable
TCP port 8080 (Zigbee2MQTT) is reachable
But SSH never gets past the initial connection
HA’s web interface doesn’t respond
Zigbee2MQTT’s web interface doesn’t respond
HomeKit stops working
I have to physically unplug/replug the Jetson to recover it

For example, ssh -vvv gets to:
debug1: Connecting to 192.168.4.33 [192.168.4.33] port 22.
debug1: Connection established.
...
debug1: Local version string SSH-2.0-OpenSSH_8.5

and then hangs. It never receives the remote SSH version string.

Interestingly, the application ports accept TCP connections, but don’t actually respond. For example:
curl -v --max-time 5 http://192.168.4.33:8123/
successfully connects, sends the HTTP GET, and then receives absolutely nothing until timing out after 5 seconds.
The same happens with port 8080.

So it seems like the Jetson/network stack is partially alive, but processes aren’t actually servicing connections.

Everything is running in Docker, so I’m wondering if this could be:
storage/SD-card I/O problems
kernel/driver lockup
memory exhaustion
Docker/containerd issue
power instability
filesystem problems
some Jetson-specific hardware/driver