This meant one of two things: IKEA had pulled out of sponsorship (highly unlikely) or TfL wanting to make sure that a press release is in place before they launch the maps (much more likely).
I notice that IKEA are already doing branding on the Motorist's Atlas. Unfortunately, (or fortunately - depending on your viewpoint) this doesn't mean we'll be seeing little IKEA icons at Neasden & Tottenham Hale stations on the actual Tube Map itself. But who knows what the future holds?
It appears that Victoria weren't being so secretive about the map and there are a number on display there.
Not sure when the last sponsored Tube Map was, as Oyster have been taking that back page for quite some time now.