We all know that words that can be used both as nouns and verbs have a different stress pattern: http://www.wordstress.info/wp-content/uploads/2014/10/Stress-Pattern-Change-noun-verb-pairs.pdf
As a non-native english speaker, I love rules. And, just like a young child, I make some (funny) mistakes when it comes to the exceptions. For instance, "award":
Because of the above-mentioned rule, I automatically pronounce the noun as "A-ward" and the verb as "a-WARd". I know that there is no "A-ward", but that's precisely my question:
Why do some pairs of verb/noun homographs not follow the stress change rules?