A decade ago, I used to work for a firm that managed multi-employer pension funds like these. We were an old school "honest" asset manager, and as a reward during the 2000's we lost clients left and right to bigger firms that promised our clients irrational returns. The pension fund trustees were gullible, and fell for every stupid pitch that promised them 20% returns with no risk. Probably they thought they could spend the overage on political contributions...
So I don't feel too much sympathy for these pension funds. In many cases they got in trouble because they ignored warnings from their long-time advisors, and listened to consultants and banksters who were in line to collect hefty fees.
Multi-employer pensions are pathological — the sponsors (companies) are jointly and severally liable, so if one goes b/k the rest have their burden increased. Death spiral.
Not so different from living in a blue state, sadly.