Impermanence NetworkManager warnings

Hello there,

Maybe I’ll have more luck here : I have an issue, or maybe this is expected, with my impermanence setup.

Whenever I nixos-rebuild switch I get those three NetworkManager related messages:

setting up /etc...
A file already exists at /var/lib/NetworkManager/timestamps!
A file already exists at /var/lib/NetworkManager/seen-bssids!
A file already exists at /var/lib/NetworkManager/secret_key!
Activation script snippet 'persist-files' failed (1)
Failed to run activate script

Should I not care or how can I get rid of these ?