I think I solved this problem myself on with my captain. If you hit F2 while already having the group leader selected, it selectes his pet if one exists. All my slaves kept selecting the herald so I changed my target group leader key to a sequence of two presses in ISBoxer, F1 followed by F2. The F1 press is to select themselves first so that it ensures that the second press of F2 selects the group leader not the group leaders pet. I just have to double tap my target group leader key and everything is fine.
I am assuming its the same with the skirmish soldiers? I didn't notice any problems when I did trouble with tuckborough in my 3 man group after making this change.
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