Challenger Bread Pan HELP!

Hello everyone!

My first post! I need some help with my baking with the Challenger Breadpan. I’ve been baking sourdough for a year now and I get wonderful results in my enameled and ceramic Dutch ovens. However, my Lodge combo cooker and Challenger Breadpan I just got are causing me problems. 
Here are the two recipes I use for basic sourdough that I have had good results with in the Dutch oven:

1) 425 g bread flour, 150 g starter (1:1:1, fed 18-24 hours prior), 300 g water, 10 g salt. Mix everything but salt and autolyse for 45 minutes. Add salt, do slap and fold for 5 minutes. Bulk ferment for 4 hours with stretch and folds every 30 minutes. Preshape, wait 20 minutes. Shape and refrigerate for 12 hours. Bake at 450 with lid on for 20 minutes, bake with lid off at 450 for 25 minutes. 
2) Tartine country bread recipe, exactly as noted. 

(all flour is King Arthur brand)

Here is my problem: My bread spread out flat and doesn’t get good oven spring when using the Lodge combo cooker or Challenger Breadpan. I also don’t get ears with my scoring like I normally do. Photo here: https://share.icloud.com/photos/07yJNwhwMyc4zd9-tmL2HbFEg#Anaheim

Any suggestions would be welcome!