Most likely cause of the issue is using of CMD instruction in php service Dockerfile.
My thouths that this CMD instruction may conflict with CMD instruction from php-fpm image.
From Dockerfile CMD reference:
There can only be one CMD instruction in a Dockerfile. If you list more than one CMD then only the last CMD will take effect.
For this time workaround was added.
Most likely cause of the issue is using of CMD instruction in php service Dockerfile.
My thouths that this CMD instruction may conflict with CMD instruction from php-fpm image.
From Dockerfile CMD reference:
For this time workaround was added.