"I'd breakfast" is a totally valid English sentence, but it doesn't mean what the Indonesian means. "To breakfast" is a verb and "I'd breakfast" means "I would breakfast". It's an old-fashioned way to say "I'd eat breakfast" but people still use it as you can easily see by Googling.
But it seems whoever wrote this one thought it was a valid way to contract "I had breakfast" which it is not. And even if it were it would be past tense, where I think the Indonesian is clearly expressing the present.
It's probably not that someone thought it's a correct way to contract "I had", it's just that Duolingo grading algorithm knows that generally it's a possible contraction but has no clue when it is correct and when it's not. So it accepts it everywhere automatically if "I had" is an accepted answer, and sometimes even suggests it.
Yeah, I'm sure that's it. The Duolingo automated contraction system can throw some serious curveballs at times.
Probably some common translations were missing originally, but now all the following are accepted:
- I have/eat breakfast
- I am having/eating breakfast
- I had/ate breakfast
So unless people are wanting to use "breakfast" as a straight up verb (which, by the way, is a legit albeit uncommon thing to do; for those who might find this unexpected, I just verified it in five dictionaries), I guess things should calm down in this thread on the English front. (Of course my knowledge of Indonesian is minimal, so if there are additional possible English tense/aspect combinations that ought to be included, that's beyond my knowledge level).
I'd breakfast makes no sense to a native English speaker. We would never say that under any circumstances. We would not even say 'I breakfast' but I'd breakfast is definitely a poor translation. It's still not fixed and it's frustrating having to write something in your own language you know not to be correct.