The instability of correlations among asset classes results in more risky allocations over time. The solution is to avoid using correlations in the development of the asset allocation strategy.
Many investors entered the markets in the wake of the 2008 financial crisis, but all they have experienced are "V-shaped recoveries." The idea that everything is V-shaped has become deeply ingrained in people.
A research has shown that correlations increase and the diversification benefits of a multi-asset class portfolio even with alternatives fail during periods of market declines.