If you do have several Digi Embedded Linux ESP projects, sharing the same nfsroot directory and you run "make install" on them, existing files from the other project will be overwritten, but files added in other projects will not be removed.
This can result in some unwanted files in the rootfs when booting with "dboot linux tftp" over the network.
To solve the issue, just run an rm -rf /exports/nfsroot-$PLATFORM/* before you run make install to avoid install results from other projects interfering your rootfs.
You can also do this from the ESP by unfolding your project in the project explorer, unfolding build, right click on rootfs and run "Rebuild Rootfs" and "Install Rootfs".
If you often want to boot several projects with different rootfs from the network, you should select disjunct nfsroot directories for them in the project properties. Drawback: to boot from an nfsroot directory with a non-standard directory name, you have to change the npath environment variable in U-Boot to match your project, e.g.:
# setenv npath /exports/nfsroot-myproject
dboot linux tftp