I've found a workaround to a bug then brutii and scipii try to load units in transport and then unload them back in next turn.

It seems if you save/load game, after ship is loaded, that naval units won't be bugged. Continue save/loading until they unload them at enemy shore, since otherwise they'll be bugged again and go back.


Brutii condition now seems the easiest to fix.
Just save/load at 2nd turn of the campaign and they'll take Apolonia.