She did also say "correct this behaviour" which is the corpo way of saying "do it or else"

And that's why you retain the email. Establishing a pattern makes the specific language less important, although in this case there's a pretty clear implication that the employee will be punished for using their full meal break.

Ianal but "voluntarily" taking a shorter lunch break is still illegal in some states. In my state, my boss would get in trouble if it could be proven that they knew I wasn't taking the full, mandatory 30 minutes.

Imo the move is to respond with a clarifying question about whether the hr person is asking them to cut breaks short while reiterating that asking them to do so is a violation of labor law and document the hell out of it.

If it happens again, then make a complaint with labor. This shows that you are operating in good faith and giving the company a chance to correct before going nuclear, which further strengthens your case if you do have to report.

Sometimes the hr person is just an idiot. I've seen suggestions like this before and it turned out the hr person literally didn't know you can't just arbitrarily deduct wages without explicit permission from the payee (and in some states, not even then).

Reply from state labor board: oh hey sorry yeah turns out there's no laws requiring breaks federally or in then vast majority of states. Maybe find a new job if you don't like it gl bro

The US Department of Labor site lists 20 states and 2 territories.

https://www.dol.gov/agencies/whd/state/meal-breaks

All 50 states though require you are compensated for your work. So if this is a non-salary position still illegal if the break period is unpaid.

Additionally if his work contract garuntees the break period that still has legal standing