And how are you configuring dnsmasq? If you are using the stock Ubuntu desktop, you will have NetworkManager depending on the dnsmasq-base package, and providing a dnsmasq server that guaranteeably starts before NM signals mountall. If you are using dnsmasq some other way - for instance, by not providing any fallback DNS servers to resolvconf that would be usable by the system between the time the network interface comes up and the time dnsmasq starts - then sure, that's not going to work. But that's nota bug in mountall; mountall has no way of knowing that the network isn't really up yet when it's supposed to be. If anything, that would be a bug in the dnsmasq package for not integrating properly with mountall.
And how are you configuring dnsmasq? If you are using the stock Ubuntu desktop, you will have NetworkManager depending on the dnsmasq-base package, and providing a dnsmasq server that guaranteeably starts before NM signals mountall. If you are using dnsmasq some other way - for instance, by not providing any fallback DNS servers to resolvconf that would be usable by the system between the time the network interface comes up and the time dnsmasq starts - then sure, that's not going to work. But that's nota bug in mountall; mountall has no way of knowing that the network isn't really up yet when it's supposed to be. If anything, that would be a bug in the dnsmasq package for not integrating properly with mountall.