hi joe
thanks for your reply.
i've managed to fix some but not all of the issue. i found that you can't edit a previously stored scan destination (which was ftp) and change it to smb, but i deleted all the ftp connections and created new smb connections for each of the updated macs.
what's now weird is that i can scan to one of the macs but not the others, even though they are setup the same. the only difference is the mac i can scan to is running 10.13.3 beta while the others are running 10.13.2. could that be it?