This is something I've noticed for a while but I want to be sure of it. I just encountered the sentence “準備したらおいで。” in context I'm fairly sure this means “Come when you're ready.” and I've encountered it many times. “準備する” however does not mean “to be ready” but “to get ready”, “to be ready” would be “準備している” or “準備ができている” if I not be mistaken. Thus, I would expect “準備してたらおいで” instead. After all, the character is beckoned to come when being ready, not when getting ready.
I've seen this multiple times “気づいたら” is of course a fixed idiom which I found counter intuitive from when I first saw it, I had expected “気づいていたら” for that meaning, the same with “帰ったら” clearly meaning “when I get home”. Again, I would have expected “帰っていたら”. Indeed “〜ていたら” does not seem to occur at all much and I don't think I've ever seen it.
So does “〜ていたら” simply not occur at all, and as such is the usage one would expect it to have assumed by “〜たら” with the difference being contextual? Can “帰ったら” also mean “when I go home” opposed to always “when I get home” with the difference being from context or does it always mean “when I get home”? and is this simply how “〜たら” works?