35-70mm f2.8 center lens delaminating prevalance?

I've been seriously looking at buying a used 35-70mm f/2.8 Nikon lens, but have recently come across a number of posts indicating a known issue with that lens. Specifically that after a number of years the center lens group has a glue that delaminates, forming a haze. Some postings suggested that this was nearly inevitable, and would occur after about 5 years.

Does anyone know how likely this really is to happen? Is it nothing to worry about or would buying a 5-10 year old copy be throwing money away?