Sandwich bread collapsed

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Hi All - what would cause a sandwich bread to collapse or cave in on all four sides after cooling? It looked absolutely beatiful after baking and the internal temp was 200 F. The recipe was from a professional site and I'm baffled. Baked in a USA bread pan with cover on (as instructed)...cooled in pan for about 15 to 25 min or so?

Can post pics if that helps..

There was another thread that talked about undercooking and the sides collapsing because they couldn't support the loaf as it cooled.  I couldn't find it, but I think the consensus was to take the loaf out of the pan and place it directly on the oven rack for the last 5 minutes of the bake.