Had the exact same experience. On line order, showed up at my assigned pick up time, then waited an hour in the pickup line - only to be told it wasn't ready yet so I'd need to wait for a few minutes.
If I had just showed up and gotten in the regular line at the restaurant I would've gotten my food faster.
And that's the last time I went to/ordered from Cafe Rio.
I felt the worst for the poor uber eats guy there - who wasted an hour of his time waiting on an order to deliver, and he only gets paid a set amount for delivery. If I was working for one of those delivery services, I'd just refuse to take anything from Cafe Rio.
I like their food OK - but they've got to fix that "to go" ordering system. It sucks.