It could be the stress from injury and surgeries. I would not limit my eating window so much every day - increasing meal frequency, at least for a few days out of the week might be helpful. Also, 1800 calories is not very much food for a guy your size and age. So maybe you should add a full sized meal for a few days of the week. When you're recovering, it's important to not put additional stresses on your body (calorie restriction, low meal frequency). It makes sense that your body would be putting fat on.