-caseInsentive doesn't seem to work for n-grams where n>1

This seems to be an issue with n-grams containing "I" .All n-grams containing "i" (in lower case) return a frequency value of 0 even when -caseInsensitive is added to the command.Is it that it only takes into account all occurrences of the n-gram in any case(lower,upper or title case) only if the provided form(case) of the n-gram exists in the corpora?