This is really the best we can do with the current situation. There is 
no mechanism in place for flagging a NEW item as needing to be changed 
and synched back to the device and adding one would be more work than 
it's worth. Ideally, the protocol should have an error status code for 
an unsupported text format, and a limit on the length of the 
description field (as it does for some other fields in other 
collections), but it does not.

The client should have a switch to disable HTML content to avoid (at 
least most of) this issue. In Mnemo 5 we should have HTML support for 
notes so this will not be an issue at that time.

  Changes have been made in Git (FRAMEWORK_5_2):

commit abd591be13570534adc8758bac41d9021aa7d5d8
Author: Michael J Rubinsky <mrubinsk@horde.org>
Date:   Tue Jul 14 10:37:45 2015 -0400

      Bug: 14045 Consistently convert html2text for ActiveSync notes.

      ...at least until Mnemo gets HTML support in the next major version.

   mnemo/lib/Api.php |    8 +++++++-
   1 files changed, 7 insertions(+), 1 deletions(-)

http://github.com/horde/horde/commit/abd591be13570534adc8758bac41d9021aa7d5d8

  Changes have been made in Git (master):

commit 436828a5bd827a33669339d1ef20b74c24bd3dd9
Author: Michael J Rubinsky <mrubinsk@horde.org>
Date:   Tue Jul 14 10:37:45 2015 -0400

      Bug: 14045 Consistently convert html2text for ActiveSync notes.

      ...at least until Mnemo gets HTML support in the next major version.

   mnemo/lib/Api.php |    8 +++++++-
   1 files changed, 7 insertions(+), 1 deletions(-)

http://github.com/horde/horde/commit/436828a5bd827a33669339d1ef20b74c24bd3dd9

If one creates a new note via ActiveSync, in function import of 
lib/Api.php the HTML is denoted to plain text via:

         case 'activesync':
             // We only support plaintext
             if ($content->body->type == 
Horde_ActiveSync::BODYPREF_TYPE_HTML) {
                 $body = 
Horde_Text_Filter::filter($content->body->data, 'Html2text');
             } else {
                 $body = $content->body->data;
             }

However, there is no such check in function replace() some lines below.

There is at least one way to produce the error:

1) create a new note on the ActiveSync device. It is denoted to plain 
text in the GUI, but remains unchanged on the device.
2) change the note on the device, Its body is sync'ed as HTML to Mnemo.

So the handling is inconsitent.

====

I don't know, if changed / converted notes should be flagged as 
changed and are sync'ed back to the device immediately, in order to 
reflect the changes. Now the user works with the original note on the 
device (incl. long subject and fancy HTML), but Horde keeps a possibly 
shortened subject and denoted body. The reference to "subject" applies 
to bug #14041.