MWI not wanted on some lines but

I have a situation where I don't want MWI on a T38G phone for some of the accounts registered. The "Subscribe for MWI" setting for the account is set to disabled yet it still gets voicemail waiting notifications on the account. I have tried firmware versions 38.70.0.115 and also 38.70.0.132 and both give the notifications.

Is there any other setting that might turn off MWI for an account that I am missing or would this be a firmware bug?