by Matteo Scaramuccia.
Hi Martin,
2.3 is the first version supporting PHP 5.4 with no errors (MDL-31167) and your specific issue has been fixed with MDL-32094.
That being said, I'm wondering why setting Moodle debug level to NONE doesn't work: since I do not have PHP 5.4 in my machine, could you post the result of your Site administration ► Server ► PHP info?
At least:
Loaded Configuration File: __________
and:
Directive Local Value Master Value
error_reporting ___________ ____________
The expected values are: e.g. /etc/php.ini, 0, 30711 i.e. 32767 - 8 - 2048.
Matteo