I only used "the US" and "Ireland" as examples. It also happens at companies where both offices are in the same timezone or if employees in one location work on

I only used "the US" and "Ireland" as examples. It also happens at companies where both offices are in the same timezone or if employees in one location work on the other location's time (the latter was the case at my last company: we had an office in the Philippines where most employees worked on US Central time to match with HQ, except for the support departments where they did shift work for 24/7 coverage).