What makes a maintenance mode message display, when a site is not in maintenance mode? In this instance, it appears that it was because a contrib module was throwing a recoverable fatal error. So there was no WSOD/ general crash but because there was an error, the maintenance mode message was being displayed. Is this possible? I suppose it's too localised to really be sure.
This question is for Drupal 6 (it can't connect to the database) is the same true for Drupal 7?
Maintenance mode is not turned on, yet I'm getting a maintenance mode message. What's more it's being displayed as a second HTML page rendered fully marked up, beneath the target page which is also rendered fully marked up: Maintenance page being rendered as an entire page load after the main page load