This is a problem with over-long MSGs. Although Avalon does not impose any restriction on the length of an MSG (I believe the maximum length for any command line is about 250 characters anyway), it is not generally wise to send MSGs of more than about 2 lines in length. This is due to the way Avalon buffers its output. It results in what Fiorella is describing.
If you have a long message to send to someone, either write a letter, or send it in more, shorter MSGs. We will look at the problem, but until further notice, please observe these fairly straightforward guidelines.