While sorting out Trakt and TMDB noticed Whose line is it anyway season numbering for 2013 to current is restarted as season 1 CW continued the seasons starting with season 9, which here is season 1, and continues to the current season run of season 18.

CW website link and proof of the continuation of the season numbering: https://www.cwtv.com/shows/whose-line-is-it-anyway/kyle-richards-2/?play=84e401d1-4f12-4346-a073-65437f54913c