We ran into an issue when setting up our new Rachio 3 that I think could be fixed server-side. I created an account and setup our controller, and then I went to share access to my wife. She signed up with her email address and I share it to, for example, firstname.lastname@example.org. She got the invite in her email and opened it, but it went to the setup controller view instead of getting access to the one I had invited her to. After logging out and back in a few times, I noticed she had signed up as Firstname.Lastname@gmail.com, with capital letters, whereas I had shared it to the lowercased version. Email addresses are not case sensitive, which is why she received my invite even though it wasn’t the same case. It appears however that the server side software that the app connects to is case sensitive though, meaning it thinks Firstname.Lastname@gmail.com and email@example.com are two separate accounts. I confirmed this by revoking the access and adding it again with the capitalized email and boom, she got in right away.
Luckily, this fix should be just a server side change; even if the app is sending up the email capitalized, the server can downcase and standardize them so it works either way. There are always complications for these sorts of changes though, so it might get more tangled, but at least in concept it’s not too tricky!