It appears that, if you execute a connector call in a decision shape, the shape will return false if the connector call returns an error. For example: a http 403 "Forbidden" or 429 "Too many requests". Http errors like these are caused by a temporary situation. Netsuite sometimes returns 403's for several minutes, and after a while it comes back to live again. Shopify often returns a 429 if you send too many requests.
Therefore, the decision shape should raise an exception and not return false if it does not return the record you are looking for. Is there a way to force an exception in this case?