Unexpected docker build cache miss after successful --no-cache

unexpected-docker-build-cache-miss.md

git checkout master # setup Dockerfile
docker-compose build # uses cache (expected)
git checkout HEAD^1 # removes some line from Dockerfile
docker-compose build # uses cache (expected)
git checkout master # adds back same line to Dockerfile
docker-compose build --no-cache # does not use input from the cache (expected)
git checkout HEAD^1 # removes same line from Dockerfile
docker-compose build # has unexpected cache miss

possibly related? moby/moby#3199

Reported this upstream to docker, moby/moby#20304