For context, I am on the Cloud for both Confluence and Jira.
When I add a receiving Synced Block into a Jira issue's Description field from a transmitting block in Confluence, the block appears while editing.
However, when I click Save, nothing appears and the synced information fails to display in the Jira description.
But if I edit the Description field again, the Synced Block with synced information is still there.