[n_u_l_l]

They messed up. The WhatsApp number they included in the first NL-Alert is the phone number of the local newspaper De Telegraaf. It’s not owned by the emergency services.

They just sent a new NL-Alert with the right WhatsApp number.

[rgj]

The fact that they sent this specific number - the anonymous tip line of the largest Dutch newspaper - probably means that someone in the emergency taskforce team was actively leaking information to the press...