Changes have been made in Git (FRAMEWORK_5_2):

commit 101fdd4e62941f645b7fa0f3283ef13d3696dddf
Author: Jan Schneider <jan@horde.org>
Date:   Tue Sep 23 15:38:45 2014 +0200

     [jan] Fix notification and alarm issues if alarm is longer than a 
day (Bug #13584).

  kronolith/docs/CHANGES |    2 ++
  kronolith/package.xml  |    2 ++
  2 files changed, 4 insertions(+), 0 deletions(-)

http://github.com/horde/horde/commit/101fdd4e62941f645b7fa0f3283ef13d3696dddf

Changes have been made in Git (FRAMEWORK_5_2):

commit 0ded4b505dc90d7a29f2242b24b48ce0601a1c0b
Author: Jan Schneider <jan@horde.org>
Date:   Tue Sep 23 15:35:36 2014 +0200

     Fix subtracting alarm time (Bug #13584).

     We only need to subtract the alarm where we set the alarm time. 
The start date
     and time for the event always keeps the same. This fixes several 
issues with
     notification text and links, and alarm messages, especially if 
the alarm time
     is longer than a day.

  kronolith/lib/Event.php |    9 +++++----
  1 files changed, 5 insertions(+), 4 deletions(-)

http://github.com/horde/horde/commit/0ded4b505dc90d7a29f2242b24b48ce0601a1c0b

Changes have been made in Git (master):

commit 46cc5c1baf69f4055f6b5df9acb1b4e8e5ca1192
Author: Jan Schneider <jan@horde.org>
Date:   Tue Sep 23 15:35:36 2014 +0200

     Fix subtracting alarm time (Bug #13584).

     We only need to subtract the alarm where we set the alarm time. 
The start date
     and time for the event always keeps the same. This fixes several 
issues with
     notification text and links, and alarm messages, especially if 
the alarm time
     is longer than a day.

  kronolith/lib/Event.php |    9 +++++----
  1 files changed, 5 insertions(+), 4 deletions(-)

http://github.com/horde/horde/commit/46cc5c1baf69f4055f6b5df9acb1b4e8e5ca1192

Please have a look at the attached patch.

There's still something wrong with "all day" events. As far as my 
testing goes, in this block

if ($this->isAllDay()) {
    if ($this->start->compareDate($end) == 0) {
        $methods['notify']['subtitle'] = sprintf(_("On %s"), 
'<strong>' . $this->start->strtime($prefs->getValue('date_format')) . 
'</strong>');

the inner if always is false, even for one day events (because they 
are stored as "from 00:00:00 on the starting day until 00:00:00 on the 
day after the event's end day").

... it should be "show wrong *date*" in the first line. The time seems 
to be OK.

Now I think this happens because of some $start vs $this->start mix-ups.
$start is modified (-= this->alarm) and used for the date, while 
$this->start is used for the time.

The alarm mails and inline notifications that Kronolith creates show a 
wrong time for the Event.

To reproduce:
1) Create an event x days ahead from now.
2) Set the reminder to email and inline, "x days before the event starts".
3) The notification/email shows the current date as start date instead 
of the correct start date x days ahead.

Is this related to this line
https://github.com/horde/horde/blob/6dd551000fbbf91a8969bcb1c8800a74d04a3745/kronolith/lib/Event.php#L2187 
?