The email server is what most often determines the date-time stamp on an outgoing message in particular, not the local machine time. It's not uncommon for email servers to be outside one's own time zone. Check to see where yours is located.
When there are time discrepancies of precisely some hour interval that's where I'd look first.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
It is better to be hated for what you are than to be loved for what you are not.
~ André Gide