Not going to point fingers on firmwares, nor the Devs, as build.props can be a bit tiresome in weeding through so much text.
Use a good document editor to search for a space next to the equal sign with another space. Replace with the equal sign without the spaces.
The other issue is using a 0 instead of false. Cannot say which setting as I cleared it out long ago. Might be with DTS, HDMI, CEC, color space... ect. As I was modifying those areas.
lastly, multiple entries for display cache. Only one loads and usually I see it is the smaller variable which is bad for large displays.
Also I have seen two variations of using an older Android build.prop entry on newer Android. Slightly different yet looks very close to the proper entry, and probably does not function, as intended.
I will post a fix for Xfinity Stream TV, as to why it detects HDMI on one box and doesn't on another.