Examining the logs from 5/3 to early 5/8, there are a total of 20 errors, most of which relate to fetching data. In this case, Cairns, and it recovered afterwards. But still, there are a number of cases where FeedMessage feed = FeedMessage.parseFrom(url.openStream()); failed in the TransitDataService, with one of these exceptions:

com.google.protobuf.InvalidProtocolBufferException: Message missing required fields: header java.net.UnknownHostException: gtfsrt.api.translink.com.au java.io.IOException: Server returned HTTP response code: 503 for URL: https://gtfsrt.api.translink.com.au/Feed/CNS

Sometimes for 30+ seconds. Note these may all be in the night in Australia anyway... but it would be good to notify in case it happens during the day.

The log has also been good for this sort of error handling. Copied locally (and left on server) as log4j.log.