Last handshake shows inaccurate duration

[gyscos]

Hi, and thanks for your work!

I noticed a very minor detail: the "last handshake" duration shown in innernet list is sometimes unexpectedly large for peers currently disconnected. Here's an example from my current setup:

  peer: minibene (QOAYO5XcS/...)
    ip: 10.43.64.2
    endpoint: x.x.x.x:54820
    last handshake: 484142 hours, 32 minutes ago
    transfer: 0 B received, 82.82 KiB sent

In practice, this should have been a few days, not 55 years (i guess the last handshake timestamp got null somehow). It was showing the proper value before.

All machines in this setup are running up-to-date archlinux.