Had this happen just a few minutes ago. I deleted both hop additions that I had, saved the recipe, exited out, selected the recipe again, selected the edit function, then re-input both hops over. After doing this, it saved properly (Though, I suppose the sort button may have worked too; it did the last time I had this error.)
I know this thread is old but this issue has been driving me insane. Seems like in some conditions, clicking the copy button fills out the UI but that data isn't stored and it errors. It doesn't happen all the time but sometimes it does. And once it happens, the whole recipe is borked. Deleting and manually adding doesn't solve the issue. It started working again after I clicked the sort button, per someone in this thread's suggestion.
Ok, that was weird. Even though "boil" was already specified, I went back in and selected it from among the options and that fixed it. THANKS!
