As discovered during investigation of
https://github.com/paritytech/polkadot-sdk/issues/3314 and
https://github.com/paritytech/polkadot-sdk/issues/3673 there are active
validators which accidentally might change their network key during
restart, that's not a safe operation when you are in the active set
because of distributed nature of DHT, so the old records would still
exist in the network until they expire 36h, so unless they have a good
reason validators should avoid changing their key when they restart
their nodes.

There is an effort in parallel to improve this situation
https://github.com/paritytech/polkadot-sdk/pull/3786, but those changes
are way more intrusive and will need more rigorous testing, additionally
they will reduce the time to less than 36h, but the propagation won't be
instant anyway, so not changing your network during restart should be
the safest way to run your node, unless you have a really good reason to
ch...