Another problem with an intangible asset deal

So, enough about Skype already. Now there is this story about how the $4 billion intangibles play by Disney may face an unexpected glitch in securing those intangible assets (see Disney Faces Copyright Claims Over Marvel Superheroes):

Heirs to the comic book artist Jack Kirby, a creator of characters and stories behind Marvel mainstays like "X-Men" and "Fantastic Four," last week sent 45 notices of copyright termination to Marvel and Disney, as well as Paramount Pictures, Sony Pictures, 20th Century Fox, Universal Pictures, and other companies that have been using the characters.
The notices expressed an intent to regain copyrights to some of Mr. Kirby's creations as early as 2014, according to a statement disclosed on Sunday by Toberoff & Associates, a law firm in Los Angeles that helped win a court ruling last year returning a share of the copyright in Superman to heirs of one of the character's creators, Jerome Siegel.

Did Disney do a complete enough job in its due diligence? According to the story:

Even before the Kirby family sent its notices, Disney was facing criticism from some Wall Street analysts who expressed concern that Marvel's complex web of copyright agreements might prevent Disney from capitalizing on some Marvel assets.

Given that Disney has been one of the savviest copyright protectors, this comes as a bit of a surprise to me. However, the story notes that:

Disney said in a statement, "the notices involved are an attempt to terminate rights 7 to 10 years from now, and involve claims that were fully considered in the acquisition."

We will have to see how this all turns out.