use traverse, then on both sides of it you need a start and end pathnodes.
-so hit "b" go to Node->Negotiation->begin where the mantle will start and use end where, well, it will end
-under node_negotiation_begin in animscript put "ai_zombie_base_mantle_over_72" the "72" can be a couple different heights ill post a picture of them.
-under that same node at previewmdl1 put "c_zom_test_t7_2_fb"
-under both beginning and end nodes at KVP (script_noteworthy custom custom_traversal)
now select your beginning node then the end one and click "w" to link them, bam they should work!
-images-
Program Files (x86)\Steam\steamapps\common\Call of Duty Black Ops III\xanim_export\ai\zombie
heres how i have it for them to mantle back and forth over a car