The base problem is that people have expected pensions to pay out like they always did in the past, before the ZIRP era. When real interest rates were positive (like they were for most of history until circa 2010-present), it was very easy to pay out the expected results by just buy and hold treasuries or gilts. When central bankers decided to cure the last recession by artificially holding real interest rates at negative levels for over a decade, pensions had to move out on the risk curve. This led to the everything bubble we have today, with the market overvalued somewhere around 100-300% compared to its historic norms. Once inflation came back, the central bankers ZIRP plans were cancelled, bonds and stocks start crashing and pension accounting no longer balances.