The lookup_post_image.js test does an update to a document, then immediately removes it, the advances a changeStream to consume the notification corresponding to the update and expects the looked up fullDocument from the updateLookup to be null since the doc was deleted. This assertion is valid if the read and write go to the same node, but in the change_streams_secondary_reads suite this assumption is invalid, leading to the test to be flaky. We should either modify the test to not make this incorrect assumption, or blacklist it from the change_streams_secondary_reads suite.