Seems like an odd date given they will be paying people for both Thanksgiving and Christmas holidays.
Why is that odd? They'll be paying them regardless.
First, 12/3 is after Thanksgiving, so they get paid for it regardless of being laid off or not, just like any other employee.
Second, Christmas and New Year's are paid holidays, so whether they're paid as part of the company holiday or paid as part of their 45-day notice, it's all the same.
The only difference is that instead of the impacted employee having to use 3 days PTO for the year-end shutdown, s/he now gets paid for those 3 days as part of their 45-day notice. But it's cheaper for Cisco to pay that than to carry everyone until after the first of the year and then let them go because you're paying them for another, what, 3 weeks? And face it, how much productive work really gets done between 12/3 and 1/2? A fraction of what normally gets done in a month the other 11 months.