Thank You Baker!
I believe that the two cameras in use had different focal points and different resolutions.
Of the resolutions was 4K so therefore it recorded a large panoramic area around POUTS. That same 4K was then cropped to 1080p creating one stylized area of video. In the future, I'm sure a 4K video will be available once storage solutions and bandwidth is more cost effective.
The other resolution was is native 1080p and required a tighter screen shot around POTUS. This causes a secondary stylized area of video where the thick white window frame can be seen right above his head.
In contrast, the 4K shot recorded a lot of "dead space" between the top of POTUS head and the thick white windows frame, but once that centered portion is cropped to 1080, you end up getting then other stylized area of video.
This is my theory. Any broadcasters can please share there options.
And I thought finding Waldo was fun. Kek!
It turns out that POTUS has some photos on his Instagram account that show no green screen was used. You can see the reflection in the window from the teleprompter and studio lights.
https://www.instagram.com/realDonaldTrump/
The Instagram photos proves no green screen was used for POTUS.
For Chuck and Nancy, screenshot of them is included from c-span and those flags are quite a distance away, to block who ever might be outside the doors.
https://www.c-span.org/video/?456774-1/speaker-pelosi-senator-schumer-deliver-democratic-response-border-security
Other anons have suggested that 100% green screen was used. I've provided images that show no green screen is in use.
That photo is a screenshot of the actual video from c-span, link is at bottom.
All digital cameras and movie cameras will always have a strong carrier color, like green for example. As for the fringing, it could be filtering effects for their faces. Sony makes movie cameras that can knock 10 years off a persons face (like for soap operas).
For Chuck and Nancy, I noticed that at the 23 second mark of the c-span video, the bottom text bar has smokiness from edge to edge and does create artifacts when overlapping Chucks jacket, near his elbow.
https://www.c-span.org/video/?456774-1/speaker-pelosi-senator-schumer-deliver-democratic-response-border-security
Other networks might have gotten a video feed from a splitter that was more saturated in green noise or not calibrated correctly.