I think you are wise to be sensitive to the fact that words and thought patterns don't always translate precisely from one language to another (particularly Japanese to English, vice versa). However, if you focus too much on the esoteric nuances, it starts to hinder progress rather than help it. You end up thinking that words don't really have any meaning (e.g. He said he burned the leaves, but did the leaves really burn? He said he defrosted the food, but did the food actually defrost?)
Now you know that the possibility exists that the action was not completed to its logical conclusion, but I would suggest that this possibility isn't unique to Japanese, and it isn't evenly distributed among all verbs.
At this point, just having that doubt alone implanted in your mind is going to be something of a speed bump for you, when in reality the ambiguity (if any) will be clarified by the context, OR, if you are speaking Japanese, the listener will ask for clarification. I think if you start your Japanese studies with the idea that Japanese verbs don't suggest conclusive action, you will end up going around in circles, forever looking for definitive qualifiers.