I have logback.xml with a syslog SuffixPattern:
"%d

{"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"}

[%thread] %logger

{30}

%level - %msg"

The 1st colon within the date is getting converted into a string of the form: <level>:

This results in invalid output like:
2012-11-30T16 <Info>: 20:31.517Z

I came up with a hack to put a colon at the start of the SuffixPattern resulting in output like:
<Info>: 2012-11-30T1620:31.517Z