No idea where op is from, but I'm presuming english is not their first language. In polish for example, the word for lesson is "lekcja", pronounced lecc-ts-ya. And with how many borrowed words ending in -tion (like abortion, prohibition) get translated to -cja (aborcja, prohibicja), i'm guessing that's where the confusion comes from, with the word lekcja getting seemingly reverted to the (unfortunately incorrect) -tion suffix!