The planner breaking on updates is common for almost all RDBMSs. They introduce optimizations that work great for 95% of customers, and some will just have queries that now act like cardinality is way off or covering indexes are missing.

This issue was one of AWS's listed reasons for tending to prefer NoSQL style databases over "more performant" RDBMS, because of the more consistent worst-case performance, even if the result is worse average-case performance, which was important in their assumptions for scalability planning.