The corners are where the insulation is usually the worst, if it's insulated at all.
When I bought my house 35 years ago, I had ice building up in the corner of my family room. After a few years, I pulled the paneling and found they had put NO insulation in the corner. Builders are either lazy or just shoddy.
1988 Coleman Sequoia - popup (1987-2007)
2012 Roo19 - hybid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10