Ping intermittently fails from iPhone

### What is the issue?

Tailscale 1.66.3
iPadOS 17.4.1
iOS 17.4.1

I noticed since a few days that I have issues connecting to the other devices in the tailnet, but that only happens to my iPhone and my iPad, while all my linux VMs and MacBook have no problems at all.

As example: I ping the iPhone tailscale ip from the Mac, and as soon as i connect the iPhone to tailscale, it starts answering the ping. And it stays like that until I open safari and try to open anything on the internet... the ping starts failing, and the page does not open. After 2-3 minutes the page finally opens, while the iPhone starts again answering at ping for a few seconds and then fails again for a long while

### Steps to reproduce

1. From an already connected device(I use a Mac), ping the Tailscale IP of an iPhone or iPad before you connect the ipad/iphone to Tailscale.
2. Connect Tailscale on iPad/iPhone
3. Confirm the ping working on Mac side.
4. While still pinging, take the iPhone and open any website in safari or other browsers.
5. Confirm the ping is not working anymore and the iPhone is not able to open any websites.

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

Nothing from my side, apart from the fact that i've updated the app. If I would not update to the latest version, it would probably work still.

### OS

iOS

### OS version

17.4.1

### Tailscale version

1.66.3

### Other software

nothing else

### Bug report

BUG-dbc64d76a904e4fe65ce368754248f252262dc68a33979ce704cf8cc6e062a97-20240527162334Z-169b6bea12767a97