Exceptions to the Rule - Solution

The title hints that something is going to be an exception to a rule, while the actual text appears to be various things that are clued and then strung together to form grammatical sentences. Looking through possible candidates for some of these (e.g. French river, actinide, or Japanese-born immigrants), we grow suspicious that these words all have the substring “EI”. In fact, we want to pick the words that fit the clue and also break the spelling rule, “I before E, (except after C).” Reading the first letter of each clued word spells out ANSWER MNEMONIC LIE, which means the answer is MNEMONIC LIE.