net-misc/seafile-client and net-misc/seafile ebuilds haven't been updated in Portage since v6.2.4, released in mid-2018. There have been 9 releases in the meantime. The current version is 7.0.1, but it is not available in Portage. Haiwen has switched release markers from "releases" to "tags", see https://github.com/haiwen/seafile-client/tags and https://github.com/haiwen/seafile/tags . Simply renaming the 6.2.4 ebuilds worked for me.
IMHO, since seafile-7.0.2 and seafile-client-7.0.2 are in the tree already this bug should be closed as resolved.