This is a bit of an esoteric problem and fix, but I didn’t see this documented anywhere else.

I originally deployed this profile to disable the iTunes welcome screen and check for updates, because I didn’t want to bother the user with prompts for updating the iTunes app.

What I didn’t realize is that also disables the Updates tab in the Apps part of iTunes. So I had to actually update the profile to keep the welcome screen off but bring the check for updates back.

Once I did that, the Updates tab reappeared.