Hello!
When rendering with vray toon (environment) enabled, the forest edge mode produces still some toonoutlines in the "invisible" or clipped part of the forest. (see images). This is one of the forest pack preset, I think it is "grass base Layer 1 - Large".

toon disabled - no visible leftover

toon enabled - extreme outlines on the "invisible parts"

toon enabled, forest excluded from outline - still some annoying leftovers.
This remembers me of the same behavior with vray toon and vray clipper, where the toon lines are also visible in the cipped area.
Because of all the limitations that the vray toon has got, I'm not a big fan of it.
I'm pretty sure this is an "error" of vray, but maybe you know some kind of workaround.
Thank you in advance!