Data corruption when saving or loading Instances that have Lists of Models

(Bug, Closed -> Fixed, Priority: Critical, Test Status: Unit tested , Reported By Bad Link: Thing 3y284oe not found, )
Data Model
Summary: Reported by Eric in May '18; finally repro'ed by me on 5/24/18. Still narrowing down the recipe, but it is clearly that we're seeing corruption when we reloading Things that have Lists of Models.