Lua Destroy field rune removes PROBLEM! Help!

[GM FaithFull]

I use tfs 0.4 DEV, 8.6 WAR server. and well I have removeRuneCharges = false
all the runes are great, nothing finishes, expect destroy field rune... If I use it, it will end and for all players also

UNREMOVABLE_FIELDS = {1497, 1498, 1499, 1505, 1506, 1507, 1508, 7465, 7466, 7467, 7468, 7469, 7470, 7471, 7472, 7473, 11094, 11095}

local function doRemoveField(cid, pos)
    local field = getTileItemByType(pos, ITEM_TYPE_MAGICFIELD)
    if(not isInArray(UNREMOVABLE_FIELDS, field.itemid)) then
        doRemoveItem(field.uid)
        doSendMagicEffect(pos, CONST_ME_POFF)
        return true
    end

    doPlayerSendDefaultCancel(cid, RETURNVALUE_NOTPOSSIBLE)
    doSendMagicEffect(getPlayerPosition(cid), CONST_ME_POFF)
    return false
end

function onCastSpell(cid, var)
    local pos = variantToPosition(var)
    if(pos.x == CONTAINER_POSITION) then
        pos = getThingPos(cid)
    end

    if(pos.x ~= 0 and pos.y ~= 0) then
        return doRemoveField(cid, pos)
    end

    doPlayerSendDefaultCancel(cid, RETURNVALUE_NOTPOSSIBLE)
    doSendMagicEffect(getPlayerPosition(cid), CONST_ME_POFF)
    return false
end

any help would be great, thank you

BTW It's runned on linux