How should we count time for incoming emails received at night or on days off from work?

ANSWER

If we are concerned that information about an incident that may constitute a potential personal data breach will be sent to us during a day or time off from work, we should remember the deadline provided by the Article 29 Working Party for conducting an "investigation" (time to examine the incident and establish that a breach has occurred). The 72-hour deadline starts running only from the moment the controller establishes that a breach has occurred. However, we warn against artificially extending this time by citing failure to read an email message.