This map has always been broken. This variant makes it slightly less broken (although something changed on the ceiling might prevent hiding on pixels on the slope). What will finally fix it is either moving nets closer together or adding angle bounce to hedgehogs or some other layout that prevents hiding.
/*
** $Id: lvm.h,v 2.5.1.1 2007/12/27 13:02:25 roberto Exp $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
#ifndef lvm_h
#define lvm_h
#include "ldo.h"
#include "lobject.h"
#include "ltm.h"
#define tostring(L,o) ((ttype(o) == LUA_TSTRING) || (luaV_tostring(L, o)))
#define tonumber(o,n) (ttype(o) == LUA_TNUMBER || \
(((o) = luaV_tonumber(o,n)) != NULL))
#define equalobj(L,o1,o2) \
(ttype(o1) == ttype(o2) && luaV_equalval(L, o1, o2))
LUAI_FUNC int luaV_lessthan (lua_State *L, const TValue *l, const TValue *r);
LUAI_FUNC int luaV_equalval (lua_State *L, const TValue *t1, const TValue *t2);
LUAI_FUNC const TValue *luaV_tonumber (const TValue *obj, TValue *n);
LUAI_FUNC int luaV_tostring (lua_State *L, StkId obj);
LUAI_FUNC void luaV_gettable (lua_State *L, const TValue *t, TValue *key,
StkId val);
LUAI_FUNC void luaV_settable (lua_State *L, const TValue *t, TValue *key,
StkId val);
LUAI_FUNC void luaV_execute (lua_State *L, int nexeccalls);
LUAI_FUNC void luaV_concat (lua_State *L, int total, int last);
#endif