Could have been cold in the kitchen. I'm too old to remember lolYes, I always use a thermometer. Even with the pullman loaf pan.
"cooling in the pan was in order to give the bread (sides) time to firm up" - just to further clarify what I mean, the whole loaf is sort of being supported by the dome of the loaf on the edge of the pan while it cools enough to support itself.
Also perhaps it was in a draft? Or very cool/cold in your kitchen? Looking again at your middle picture the top seems a bit 'wrinkled' as in shrinking or collapsing as well. Could just be the picture - even though a picture is worth a thousand words they can also be very deceiving! LOL
I'll try cooling hit next time, and maybe let it bake a few more minutes.
I really liked the consistency of the past time, but I am curious as to what caused the deformation and how I can correct it. If the consistency changes ( for the worse ) as a result, ill just get used to eating warped bread.