Hello everyone,
As this issue is growing on it, seems most of the cases fall under this category and so should try the following solutions:
If you are experiencing low resolution textures when running on extreme, its most likely that you don’t have enough video memory.
You can force an override by ticking the unlimited video memory tick box in the advanced graphics settings however this may impact performance.
Another thing, the vegetation alpha is an option that should be set to off for all but the most powerful rigs.
A workaround has been found that could help some of you: by setting your game in windows mode you shouldn't experience texture issues any more.
If you still have this issue, please update your post stating you have tried these solutions and that it hasn't worked. If it did work could you please update your post to state that instead?