Since we don't show schema and don't handle schema for condition node, schema propagation fails in UI.
It fails in this specific case as the condition node doesn't have output schema and the error transform looks for input schema for previous stage.
The intermittent fix is to handle Condition node just like any other node but hide the schema while rendering node configuration. This will help avoid js error.
The schema propagation is still not fixed for all nodes. The user still has to click through all the nodes in the path to get the right schema for the last node in the path. (Existing JIRA: https://issues.cask.co/browse/CDAP-10125)