Okay, so the label was misinformed and it really is true that Immortal is breaking up. The label's message, straight from the Nuclear Blast website:

Well, sad news.. Although stated differently earlier as it seemed as if the band only wanted to take a long break, here’s the 100% official news, directly from the band and management:
"After 13 years and 7 albums we have decided to stop working with Immortal due to personal reasons. A great thanks to all our fans worldwide who helped us making Immortal superb through all this time.
Abbath, Demonaz, Horgh"

Those of you in the UK are probably already well aware, but singer/songwriter Magnet aka Even Johansen has been racking up quite a portfolio of gushing reviews. Check out this profile from MIC Norway.