We do still appear to have intermittent issues with the tracker not being able to respond to all requests that it is given, which results in temporary errors such as the 502 error. We are aware of the issue and are working to resolve it, but given the nature of what all is required, it's a rather big job to say the least. Please be patient and continue to try to seed your torrents. They will eventually connect.
Sorry for the inconvenience. I too am affected by this periodically.