step one: start game, go to menu options hotkeys and go to protoss, select nexus, bind probe to S. coz i like to use s for scv and probe so any race i play i d use the same key.
step two: go to menu tutorials then beginner guide, enter the game and back out, go to hotkeys again now u will see a greater list with campaign units too. go to protoss not story, select nexus u will see there is a stop command which technically doesnt exist in game but it is here in the interface and it conflicts with other commands. unlike terran cmd center, S for stop only applies when its afloat, and doesnt conflict with S to produce SCV. that stop cmd shouldnt appear under nexus at all, and i cannot use S due to this bug. however during tutorial in game menu hotkey options this issue doesnt not apply, there is no stop cmd in the binds.
a work around i found: start a custom game and back out to main screen so ur hotkey list shows multiplayer only. set S to stop for global and bind an alternative key for stop. in my case i have Y, so S and Y both are for the stop cmd. now start tutorial and switch over to campaign binds, u will see in game u still can use both S and Y and hotkey binds are still set correctly as in mp. now quit tutorial and access hotkeys via main screen, click nexus, u will see S for probe, Y for stop, click on stop cmd it will show only Y as main and no alternative. but global stop is not displayed as unbound, which is a good thing. do not change anything just cancel the menu.
after u go back to custom game u will still see S for stop as main and Y as alternative cmd. if it doesnt show this but shows Y is main instead, then repeat this process, should work afterwards, sometimes it may revert by itself the 1st save. this way it allows me to avoid all conflicts and still use S for stop and SCV/probe at the same time. although the campaign key list displays it wrong. however as magically as this works, it doesnt mean there isnt such a bug, i still hope it gets noticed and fixed sometimes soon.
simple, just get rid of the stop cmd from nexus in the campaign keybind list, just like how it isnt even there under nexus in the multiplayer-only hotkey list. im sure this is unintended coz no other non-liftable building has a stop cmd, liftable structures only show S when lifted and after it land S disappears, so u can use S to make a unit. doesnt make sense that this one structure has it there when it cannot even move. and ofc when producing probes u press ESC to cancel the production queue, thats another story, has nothing to do with stop, as stop its current movement when there is none.
many thx in adv appreciate if someone can look into this
kind regards