tailscale sometimes stops announcing `PUBLIC_IP:LISTENING_PORT` as endpoint

### What is the issue?

Hi,

I've found that usually tailscale announces `DISCOVERED_PUBLIC_IP:LISTENING_PORT` as possible endpoint. I'm able to 'forward' port on router so I changed `LISTENING_PORT` on all important clients to be unique and configured router to forward that port.

So I've followed:
- `pihole` listens on port `41646` and this port is forwarded on router to LAN address of that machine
- `storr` listens on port `41648` and this port is forwarded on router to LAN address of `storr`

It works initially but for some unknown reason `pihole` machine stops announcing that endpoint.. Usually reboot fixes this for some time.. At the same time `LAN_IP:41646` is still announced.

I've verified that once this happens port forwarding works (I can send something via `nc -u` to PUBLIC_IP:41646 and capture this on `pihole` via tcpdump.

Both machines are LXC containers with bridged network to router.

Any way to always announce of `PUBLIC_IP:LISTENING_PORT`?

pihole bug: BUG-433c4ffd2ed14573d8a2a6132f3fc38dc16f367593a5100792552d2828e461eb-20241229140805Z-d81e4d57c4615eed
storr: BUG-c98477da564c543ea82b6c5ad88a82d852479d2d3df1e5f801b82904d6187301-20241229141014Z-91bec7b9c8aefd56

### Steps to reproduce

_No response_

### Are there any recent changes that introduced the issue?

_No response_

### OS

Linux

### OS version

Debian 12 LXC container

### Tailscale version

1.78.1

### Other software

_No response_

### Bug report

BUG-433c4ffd2ed14573d8a2a6132f3fc38dc16f367593a5100792552d2828e461eb-20241229140805Z-d81e4d57c4615eed