Looking at the UnitAI file in corral.diff and comparing to the current file, it looks like UnitAI has changed quite a bit in 19 months. But I think UnitAI is where the problem of Animal garrisoning happens.
I solved it guys!! Simply, instead of doing "cmd+click" or "ctrl+click", I used the touching way, i.e two fingers on the pad + click, it works. Sorry for the disturbance (even if it is true that what worked before doesn't work anymore).