Thank you, Mr. Cooper. My issue is resolved. Firstly, I did not have two instances of Objectflow since I've been using only Orbx Central. Therefore, I checked and found no instance of Objectflow installed into my P3Dv5 Add-ons folder (as expected). To assist anyone else with similar problems, I took the following steps to resolve mine:
Un-installed Objectflow from my Main Library (the Library Orbx Central automatically creates).
I created a new folder and named it "ObjectFlow Custom," making sure not to install it to my P3D root folder, or directly into a device drive, i.e., (D:), or a directory (folder) that already contains other files.
Re-installed Objectflow (this time into the newly created folder: "Objectflow Custom.")
Enabled ObjectFlow when prompted upon launching P3dv5.
So, everything is back to normal, no weird black textures on runway 01L ESSA. As a matter of fact, my issues of having no trees adjacent to airport 11s is also resolved.
