Debian reconsiders init-system diversity

I agree. It sounds like some dependency specification problem. I see it as akin to "parallel build is busted, but the serial build works". Well, this means your rules aren't listing their dependencies properly. The right fix is to find that missing link and fix it, not say "well, then just use `-j1` and be happy". Granted, systemd is at times tight lipped about some of these things, but it takes some analysis of the logs of services and the systemd service event logs to figure out.