probably because you have the ALT+1 hotkey assigned to two mapped keys.
ISB42 - Custom Hotkeys -> ALT +Mouse1 (which has a hotkey of ALT+1) and
Classic Mixed team -> Sheep (which also has a hotkey of ALT+1).
They also both end up sending ALT+1, so the custom hotkeys one is sending ALT+1 to all windows. so if the Sheepers have targets and are not on cooldown, they'll both Sheep (and in fact all the toons will do whatever they have on ALT+1).
/ed
If you don't want that Key Map active on this character set, then use the Blacklist (you might want to do this anyway for the Retail Druid key map)
AND
for reference, this assignment below, is for the initial state of the key map when the team is started, and it means this key map will start the session being loaded (or On if you like).
But because of the Toggle you can end up loading other key maps later on, if you don't blacklist them....