[imp] Mails not shown when Replying or Forwarding

[Ruben Squartini]

Hi Michael!

Finally we installed (the pear way) the latest version of everything (Horde
5.1.1, Imp 6.1.2) and thios behavior persists.

The new thing about this is that something is shown in the logs:

2013-06-27T12:38:44+00:00 WARN: HORDE [imp] PHP ERROR: json_encode():
Invalid UTF-8 sequence in argument [pid 18931 on line 242 of
"/usr/share/php/Horde/Serialize.php"]
2013-06-27T12:39:16+00:00 WARN: HORDE [imp] PHP ERROR: json_encode():
Invalid UTF-8 sequence in argument [pid 18974 on line 242 of
"/usr/share/php/Horde/Serialize.php"]

Could it be that this problem of malformed /wring chars that doesn't belong
to the proper charset is affecting something else?

Regards,
Ruben.

PS: If you need I can resend you the failing mails.