Or when you melt an $85.00 blank. It happens. Total margin killer.

I like this. It's a Nomex pad. I used it when I was doing die sub on flat items. It's stiffer then a pillow. but still has give so you don't get the hard edge.
You do want to put a teflon sheet on when you have a print facing it as it will pick up some of the fibers.

We press a ton of DTF, sometimes just laying the shirt on and pressing say the front and back together doesn't work as well for us. So threading the shirt on the platen or pillow, makes it the correct heat.

But there are different factors in every shop.

As far as ink failure on top colors, you'll ruin the shirt long before you see any issues there.

The only time over-flashing is an issue can be on some high polyester items, as excess heat exacerbates dye migration.  But that is easily solved with any decent ink.

Although the "permanent" pillow underneath would help to equalize pressure due to uneven thickness of seams and such, it isn't nearly as effective in reducing the pressure marks they cause.

Does the pillow inside the shirt reduce that? Or is there another method?

It does seem the press marks from from the shape of the pallet, and not the heating panel. I need to look at my press again, but the pallet has more rounded corners compared to the heat panel itself, and that is what I am seeing on the shirts, the more rounded corners. So that tells me they are coming from the pallet and not the panel.