Windows GUI - inconsistent display of nodes and shared nodes

### What is the issue?

Shared nodes aren't properly displayed in the Windows GUI consistently.

It appears to be the result of user switching. I can't consistently replicate this, but when I switch users, the results will change.

### Steps to reproduce

Repro:

1. Open Windows Gui
2. Network Devices
3. My Devices
4. I only see the 3 devices shared in. This happens 90% of the time. I would expect to see all my devices listed here.

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

_No response_

### OS

Windows

### OS version

10

### Tailscale version

1.66.3, 1.66.4

### Other software

_No response_

### Bug report

BUG-1bb78df41b34e367ad7db398d070b1da3aab50c81c10fc7507e394ac427d866b-20240517015422Z-2111e126ad66b047