Try verifying the mod through the launcher.

Actually the road has many obstacles (rocks, bushes, fences, trees) for 300m.

https://dev.cup-arma3.org/rTERRAINSMAPSSVN13

Also both airfields on Takistan need to rehire their gardeners as both runways/taxiways are overgrown with grass, and the road leaving North from Loy Manara airfield has some sort of temporal glitch possibly into another universe

I found the same bug on Takistan. Runway missing on Loy-manara Airfield, and Rasman Airbase.
https://steamcommunity.com/sharedfiles/filedetails/?id=1597705158

From Oukej on Reddit:

New-ish - rather fixed - since https://forums.bistudio.com/topic/150500-development-branch-captains-ai-log/page-4#entry2901558
The layer is an approximation. Meaning AI's vision won't be blocked by one leaf that's higher than the rest of the clutter and conversely where player can utilize small gaps between the leaves the AI can't. Also changes in clutter (flatting it by rolling) are ignored. But yes, a fully opaque clutter that's higher than AI character's eyes will eventually block its vision completely :) That is also why (not only) for Tanoa the AIAvoidStance property in cfgSurfaces was introduced. More info in https://forums.bistudio.com/topic/150500-development-branch-captains-ai-log/page-5#entry3023425

Thanks, found the issue.
Going to look at making a script to check other CUPs Terrain Assets for similar problem

This might be of use when debugging, I've not had a chance to check it in-game as it's code I hacked out of an older mission. Just needs a marker placed on the centre of the map called marker1.

No worries, glad this is cleared up

Ahh ... I see said the blind man, I left out CUP Terrains Maps in the launcher because I only wanted the original OFP maps active, thanks for the heads-up Alwarren, the error was mine - sorry my bad.

Let me repeat that. In order to use the CWA maps, you must load

Yes, I downloaded CUP Terrains 1.4.0 CWA Maps.

Are you loading CUP Terrains Maps as well? CWA maps depend on it.

Yes, I downloaded CUP Terrains CWA Maps.

Are you only loading Core? You also need at least one map, either CUP Terrain Pack - Maps or a custom user map.

I download from the google drive link from the CUP download page, the zip file was unpacked using 7zip 16.02 portable.

where did you download the mod from? are you sure the download is not corrupted? if it was from steam workshop try going in the arma 3 launcher > mods panel > click on CUP terrains core and then repair, then try again.