Same, its always during this time.I used to get the 502 bad gateway message between 09:10 and 09:20 GMT which was when the server was backed up. I've not been here at that time of day for the last few days so I don't know if it still does it. (Those of you in different time zones will need to find out when that is where you live)
During the 12 hour forum 'outage' (which for me was 17:45 on 31 March to 05:53 on 1 April) the forum did load but although I could read everything I couldn't post anything.