[imp] Logging level ignored?

[Arjen de Korte]

I'm seeing the follow PHP errors being logged when users access Horde  
through a smartphone:

2011-05-28T19:47:59+02:00 NOTICE: HORDE [imp] PHP ERROR: Undefined  
variable: output [pid 11708 on line 45 of  
"/srv/www/htdocs/horde4/imp/lib/Tree/Jquerymobile.php"]
2011-05-28T19:47:59+02:00 NOTICE: HORDE [imp] PHP ERROR: Undefined  
variable: output [pid 11708 on line 49 of  
"/srv/www/htdocs/horde4/imp/lib/Tree/Jquerymobile.php"]
2011-05-28T19:47:59+02:00 NOTICE: HORDE [imp] PHP ERROR: Undefined  
variable: output [pid 11708 on line 45 of  
"/srv/www/htdocs/horde4/imp/lib/Tree/Jquerymobile.php"]
2011-05-28T19:47:59+02:00 NOTICE: HORDE [imp] PHP ERROR: Undefined  
variable: output [pid 11708 on line 49 of  
"/srv/www/htdocs/horde4/imp/lib/Tree/Jquerymobile.php"]

I don't know how bad this is, but it puzzles me, because I have set  
the logging level to WARNING (and NOTICE is below that) so I would  
expect this not to be logged at all. Also all log-ins are logged at  
the same level.

Best regards, Arjen