I'm fairly certain I filed this issue previously, but couldn't find it.
A user commented that they were missing a project (https://www.synapse.org/#!Synapse:syn16804329) in a Project View table (https://www.synapse.org/#!Synapse:syn11673548/) embedded in a wiki (https://www.synapse.org/#!Synapse:syn11645282/wiki/519717). I checked and confirmed that it was missing - I had created the project and added it to the view's scope recently (2018-09-12). The new project only showed up when I went to the view table itself first. Then it showed up in the query on the wiki.
This is problem as users don't use the view table itself, they expect to go to the Wiki where the table is shown and get the most recent list of projects.