Well, in all my years with Skyrim, this has been normal. I have always been able to clip the camera through walls, even capable when I played on the xbox 360 back in 2011. As for your second question, I think I know what you mean by this. And I actually have never investigated it as an issue, but being as you are curious, I'll take a stab and chalk it up to the fact that the main menu and all loading screens are frame locked at 32, so I am guessing this might maybe cause a slow down on the rendering, and if you pay attention to when this is very briefly occurring. I am almost positive that the frames shoot up to as high as they are allowed, so this fast instant influx of frames perhaps hurries whats left. Perhaps it's a priority issue with the rendering part, or maybe it's just another mistake by Bethesda with no apparent reason, but none the less causes us to asks questions. Like why/how did they screw up there own configs (the inis) and many many more. That's my two cents.
EDIT: just had another thought, might make more sense if answer is yes. Are you using an ENB preset (graphically and color correction wise)? Most people these days do, I however do not anymore, I have way in the past. I haven't touched anything ENB related in a long time, so can't say for sure, but maybe the color correction of the ENB only loads in right at the end of the load? Or I am aware of many mods that make changes regarding colors, that work in conjunction with the ENB, and perhaps it is related to those mods being loaded in late.
Edited by CovertSlinky, 17 September 2017 - 11:17 PM.