FYI: I searched for this issue but all related topics are more than a year old, and provided no resolution.
After updating Domain Mapping plugin to v.4.2.0 I am seeing numerous PHP warnings like these in my error logs...
[22-Sep-2014 17:47:27 UTC] PHP Warning: include_once(/home/tripawds/public_html/wp-content/sunrise.php) [function.include-once]: failed to open stream: No such file or directory in /home/tripawds/public_html/wp-includes/ms-settings.php on line 18
[22-Sep-2014 17:47:27 UTC] PHP Warning: include_once() [function.include]: Failed opening '/home/tripawds/public_html/wp-content/sunrise.php' for inclusion (include_path='.:disappointed:usr/lib/php:disappointed:usr/local/lib/php') in /home/tripawds/public_html/wp-includes/ms-settings.php on line 18
I also notice that the changelog in the new version say
* Changed how sunrise is maintained
I have confirmed that I uploaded the new sunrise.php file to wp-content/
I also confirmed SUNRISE is 'on' in wp-config.
Mapped domains are still loading sites as expected, but I am concerned about the ever-growing number of these new errors in the logs.
Thanks in advance for any feedback!