H1B Layoff When does the 60-day grace period start if payroll continues for 2 months?

[HMS]

I have been laid off on June 16, 2020 as part of COVID restructuring. In the separation memo, I was informed that my last day of employment will be the last day of salary continuation - which is Aug 16. Although, my company's lawyer said that my grace period of 60 days will start on June 16 itself. Requesting clarity. Thanks

[R78]

If you are still on the payroll (including salary+benefits), what you have received is an advance notice/letter of termination dated June 16th.
You are still an employee through the final / termination date (August 16).
Therefore your 60 days would start from Aug 16

If the letter dated June 16th mentioned that you are terminated "effective immediately" and will receive severance+health benefits of 60 days, then your clock would have started on June 16th.