Hi dispnev,
With the 2.4 workaround you should not be seeing the OS X bug that mixes up the monitors.
But there may be other reasons for a lost layout. For example problems in reading reliably the monitor's EDID or simply a bug in our SW.
Can you send to us the logs collected just after a wrong layout has come up?
The log tool is at
http://www.displaylink.com/support/ticket.php?id=269
You can attach the logs here or send them through
http://www.displaylink.com/support/ask_question.php
Thank you,
Carlo