Hi Jeroen,
Short answer: I haven't seen that issue. But I have some suggestions/questions if you have time to indulge me. =)
I have to ask this first. Are you sure that you need to spy the Outlook user interface? If the purpose is to read mail from shared mailboxes, it is possible to do this programmatically. You can write custom code to accomplish reading from shared mailboxes.
Or, there is a new-ish VBO available from the Digital Exchange from NEOOPS that comes with an action for that. I haven't tested that action, but I imagine that it works if it's on the Digital Exchange. Try it out here: https://digitalexchange.blueprism.com/dx/entry/3351/solution/neoops-ms-…
As far as AA differences go between machines, is this the same application model (and same object) that is being used between the two? Would you mind taking screenshots of the part of Outlook that you're spying? I don't know that I have an answer, but I wouldn't mind trying it out myself.
Respectfully,
Dave
Dave Morris, 3Ci at Southern Company