OK, I have asked Claude’s opinion on the topic. Says that indexes are rebuilt anytime the boot is classified as a cold boot which is what happens. Says it’s a cold boot based upon “last synced cache instruction ID” that is keyed on Environment.MachineName. Says since hostname keeps changing in Docker, it’s always a cold boot. Recommends setting the hostname when starting the container.
So… updated my Docker Compose config with an hostname. Now going to run more tests and figure out whether that solves the problem. Will report!