"He cooked and ate"
Translation:Akapika na akala
Using na with the -ka- tense is not wrong, it's just not necessary, but you can use it to emphasise the "and" a bit. You can also use halafu with the -ka- tense, which is also redundant, but, again, used for emphasis.
I've read somewhere that stories sometimes do start with just the -ka- tense immediately to give the listener/reader a sense of being thrown into the middle of the action or something like that ... but I don't think I've actually come across examples of that except here. In any case, the tips and notes need to be added to to avoid giving "rules" that are not entirely accurate and the most common and useful structures (ie. here the -li- and then -ka- structure) should be the ones that are presented most of the time (with the alternatives also accepted as correct answers when typing).