If less projects were displayed then the task had I would understand display ... but it looks like it just displays it if there is 5 projects on a task, but displays them all anyways.

My versions
centos 6
nginx 1.x from webtatic
php 5.6.x from webtatic
phabricator rP2c67d9c8ace2800ec618549963c4036e92cb3a9b (Fri, Mar 4)
arcanist rARC1439aaa871837031faa1ef26b81f1fb08e4a41e7 (Fri, Mar 4)
phutil rPHU76425eaa812572cc02487db79f2dd43d93e3085f (Fri, Mar 4)

Steps

• Add 5 projects to a task, in my case: "Problem", "Composer", "PHP", "Devops Team", "Satis"
• Go view a "Open Tasks" report, the task will display all 5 projects but also a ... which then lists all 5 projects on hover.