Help - Function Configuration not saving.

Help - Function Configuration not saving.

I have a custom email notification that doesn't
keep my string settings in the "Function Configuration":

Argument name---------Field Name

toaddress----------------Email
Ace-----------------------Ace
Cust_Name--------------Cust_Name

When I save and go back into editing,
the toaddress and Cust_name arguments
have their field names changed to "update"
(as opposed to "email" & "Cust_Name")

So the configuration swaps an assigned field to another
without any notice and makes the emailnotification function
completely useless.

I tried erasing custom functions and start from scratch...

If you ask what kind of argument I have here it is:

Function name: Email
Namespace: emailnotification
Return Type: void
Specify arguments: toaddress = string
Ace = string
Cust_Name= string

Any idea as to what could happen that makes my
configuration swap a field for another?