diff --git a/api.lua b/api.lua
index 088d513..e38c04b 100644
--- a/api.lua
+++ b/api.lua
@@ -6,7 +6,7 @@ local use_cmi = minetest.global_exists("cmi")
 
 mobs = {
 	mod = "redo",
-	version = "20200407",
+	version = "20200411",
 	intllib = S,
 	invis = minetest.global_exists("invisibility") and invisibility or {}
 }
@@ -1007,6 +1007,9 @@ function mob_class:do_jump()
 	local pos = self.object:get_pos()
 	local yaw = self.object:get_yaw()
 
+	-- sanity check
+	if not yaw then return false end
+
 	-- what is mob standing on?
 	pos.y = pos.y + self.collisionbox[2] - 0.2