Configuration option being overwritten

[dantian.ap at optusnet.com.au]

We have problem with Web Bug Replacement option
We set it to our intranet but mailscanner  replaces it with its setting again, every upgrade!
I think is a bug, as if we set to custom it should stay custom like all other custom sets

Why I think so?
This setting is to prevent third party knowing if message read and privacy, and maybe other reasons.

All mailscanner is doing is change the third party to itself, so mailscanner gets see hits and IP's this I feel good for default for those not wanting to set local, but  bad, very bad when it replaces custom intranet with itself again every time, defeats most purpose, please I ask for this bug to be fixed.

Best,
Dantian Apreuvianty