Comment 5 for bug 1899902

> un-commenting the Wants bit does the trick and get everything to start in the expected order.

> Is this just the expected systemd behaviour

yes.

After= only causes the service to start after the requested unit(s) when part of a single "transaction", like bootup (i.e. when the transaction is starting multi-user.target or similar).

Calling systemctl start with multiple services doesn't put them into the same transaction, so each is started completely independently of each other.