Thanks for your bug report. I have not been able to reproduce any issues so far with how echo-message or $parseem are working.

Here are the steps that I followed to try to reproduce your issue:

1) Install a clean copy of mIRC using portable mode to the documents folder with no scripts or addons.
2) Run this copy of mIRC.
3) Connect to the server using /server -i nick1
4) Connect to the server using /server -m -i nick2
5) Open two debug windows for both status windows
6) Open a query window from nick1 to nick2
7) Open a query window from nick2 to nick1
8) Send a message from nick1 to nick2

When I follow the above steps on Snoonet, I see:

1) nick1 sends one message to nick2.
2) nick2 receives one message, $parseem is $false, and should be since nick2 is only receiving a message.
3) nick1 receives an echo and $parseem is $true for the echo, $false for all other events.

If you follow the above steps, are you able to reproduce the issue?