While working on the Symfony Demo app (see symfony/demo#572) we stumbled upon the issue reported in #22561. In that PR they question this behavior, but here I'm talking strictly about the error message itself:

Symfony\Component\DependencyInjection\Exception\EnvParameterException:
Incompatible use of dynamic environment variables "DATABASE_URL" found in parameters.

I can't understand the error message .. and it gives me no clue about how to fix this problem. Can we please improve it? Thanks!