Why does regexp ignore the letter p?

Question

PHP

such a topic that filter input with parameters

FILTER_VALIDATE_REGEXP,'~^[a-za-yayo0-9-]{3,30}\.[a-za-yayo]{2,10}$~'

does not miss the letter p ... although all the others pass, where is the jamb?
solution found
~^[a-zа-яё0-9-]{3,30}\.[a-zа-яё]{2,10}$~u
but
now a similar problem in htaccess settings/([a-za-yayo0-9-.]+)/