When a Jira Connector is set up to sync Jira Initiatives bidirectionally to a SS Project, the set of rows which are synced is generated when the Connector is created or restarted. If an Initiative is updated such that it no longer matches the Connector's JQL filter, I would have expected the Connector to place the corresponding row in the SS project into the "Filtered out by Connector" group. This is not happening.
The use case for this is pretty straightforward. If a SS Project is set up to track a release, for example, but the Initiatives which make up that release are changing over time, the Connector does not support this use case.
Once the Connector is running one of the Initiatives is moved to a different release (by updating it's Fix Version), then the SS Project becomes out of date. The Initiative is no longer part of the release, it's no longer picked up by the Connector's JQL filter, yet it remains looking like any other row in the SS Project.
The only direct workaround to this issue is to manually restart the Connector. Only the person who created the Connector can do that, so this workaround is not ideal.