Are there any known issues around multi threaded invoicing using 2 AOS instances in MS Dynamics AX 2009 SP 1 ?

There are no known issues currently in terms of the technical reliability of the AOS being able to handle multi threaded batch tasks. What is important here is that you review/ check the X++ code in terms of being ready to really benefit from running in a multi threaded batch task. The following blog post explain more in detail what I mean here:

http://blogs.msdn.com/b/axsupport/archive/2011/04/13/threading-in-dynamics-ax.aspx

We're always looking for feedback and would like to hear from you. Please head to the Dynamics 365 Community to start a discussion, ask questions, and tell us what you think!