Trouble with KAF Honey Oatmeal Sandwich Loaf

I made a loaf of KAF Oatmeal Sandwich loaf.  I think the dough may have been a little wet.  It rose nicely, I flattened it out into a nice rectangle, dimpled it wth my fingers, rolled it up, closed the seams and let it rise for 90 minutes until 1-1/2" above pan as directed.

I baked it at 350 for 50 minutes until the internal temp was a little over 190.

It was crowning nicely when I checked it after 25 minutes.  I didn't cover it with foil as directed, just let it cook.  When it came time to remove it, the top had completey flattened, cross section was basically a rectangle with a light crown.  Also, the inside is a little undercooked, probably should have cooked for a bit longer.  Also, the bread seems to tear easily, for instance whn spreading some butter.

Why do my loaves collapse during final stages of cooking?

Why does bread tear easily and not have a little stretch to it?

Here is a link to the orginal KAF recipe:

http://www.kingarthurflour.com/recipes/honey-oatmeal-bread-recipe

Thanks