RemoteSyslogAppender sends log messages containing newline characters to syslog, however the syslog RFC 3164 states that the message portion of the syslog packet can only contain visible ASCII characters and spaces. This causes multiline log messages to render on a single line in at least some instances.
The solution appears to be sending each line of the log message as a separate syslog packet. I have modified RemoteSyslogAppender to support this behavior and will provide a patch file.
Here is the relevant portion of the RFC:
4.1.3 MSG Part of a syslog Packet
The MSG part will fill the remainder of the syslog packet. This will
usually contain some additional information of the process that
generated the message, and then the text of the message. There is no
ending delimiter to this part. The MSG part of the syslog packet
MUST contain visible (printing) characters. The code set
traditionally and most often used has also been seven-bit ASCII in an
eight-bit field like that used in the PRI and HEADER parts. In this
code set, the only allowable characters are the ABNF VCHAR values
(%d33-126) and spaces (SP value %d32). However, no indication of the
code set used within the MSG is required, nor is it expected. Other
code sets MAY be used as long as the characters used in the MSG are
exclusively visible characters and spaces similar to those described
above. The selection of a code set used in the MSG part SHOULD be
made with thoughts of the intended receiver. A message containing
characters in a code set that cannot be viewed or understood by a
recipient will yield no information of value to an operator or
administrator looking at it.