I have been trying to use nested containers in version 3.19 and I am finding the nested version of lxd in the container is still 3.0.3, the default on ubuntu server prior to installing the 3.19 snap package. In this normal when using snap packages?
There is no LXD 3.19 yet, it will be released next week.
By default, Ubuntu 18.04 comes with the deb package of LXD 3.0.x. So, by default the host and each newly created Ubuntu container will have LXD 3.0.x, and each time you will need to replace with the snap (if you need 3.18).