About Forza 7, the game got patched several times i guess since you are talking about about it in the past.
What you noticed, i never did. Last time i played was 10 days ago. It looks and plays fantastic. Maybe you should check / turn off, up or down motion compensation of your tv. Just my opinion.
Forza 7 is pristine for me. The most impressive game I've played on the Xbox one x. I echo the sentiment of checking you tv settings. Improper sharpness or edge enhancements could cause this.
I have a properly calibrated panel and I wouldn't use any sort of picture processing or edge enhancement on any game hardware, it really defeats the purpose of having an accurately calibrated panel if you do that.
The shimmer you get from aliasing actually looks quite different to artificial shimmer that could be introduced by poor picture processing from a panel, what happens with Forza 7 is simply an effect of aliasing on certain objects on the screen and because the image quality is so high it can be more noticeable that perhaps it would be in a game with lower image quality.
Forza 7 is an incredible looking game on both version of the Xbox for me, in particularly the X version but the issue stems from the anti-aliasing solution not quite holding up to the higher quality PC anti-aliasing implementation, which is understandable, but as people have previously discussed on GAF it can really stand out now that the game is running with such good image quality in other areas.
I know that people have different preferences in terms of image quality but for me I would rather that they worked with a higher quality anti-aliasing implementation and used resources that are currently used elsewhere. Or at least offered an option to do that in the settings menu so that people can choose what works best for them, I'm not sure it will happen but I do try and be optimistic about these things. ��