It's not a great idea just to wire the two regulator outputs together, they're bound to fight!
No idea how to use Altium, it's too expensive for me, but I'm pretty sure there will be a circuit check somewhere in the app, you should try running that to identify any 'built-in' errors.
No idea how to use Altium, it's too expensive for me, but I'm pretty sure there will be a circuit check somewhere in the app, you should try running that to identify any 'built-in' errors.