Using ENBSeries.asi on UGMP causes some display bugs, in fact it makes some buildings/roads/objects/models/texture (choose the right one) disappear.
As you can see here, it works perfectly on Bullyworth map https://streamable.com/8pjhxs
I turned it on/off multiple times during the video and there is no problem.
It looks beautiful btw :)
As you can see here at the beginning, it works pretty well too in Los Santos : https://www.youtube.com/watch?v=RRKKiYgkWcA
(there is a weird white thing who appears on the screen but anyway, that's not the real problem)
Jump at 0:28 https://youtu.be/RRKKiYgkWcA?t=28
You'll still notice this weird line on the edge of the screen but you'll also notice that some roads and buildings simply disappear when ENB is on, and it comes back when ENB is off. Since it's only appearing on VC/LC, I'm sure you can do something about it and it will be a very good news!