Not it’s not. It should not modify your FOV in any way. It just scales the rendering resolution.
In the 4.14, I never had any issue like this weither using 50 or 150 as value.
I tihnk the screen percentage may be modifying your field of view and as it is a “Percentage” I recommend not going above 100. Although, with Screen Percentage, correct me if I’m wrong but I recall VizualTek mentioning he had issues when he had it set to 100. So I would recommend setting it to 99 at most.
I HAVE THE SAME ISSUE!!! Please fix it, I have almost had a fail presentation because last moment I wanted to change it to 150% and it looks like Zoomed in and it’s like broken eyes or watching it from cross eyes. Very bad not useful at all. This is critical bug, I hope they will fix it in 4.18