Favorite or favori !

Question

Why favorite (feminin) and not favori when Mon (masculin) activité est le ski (masculin) de fond ? Have missed something ?

Maarten Kamp · Accepted Answer

Stephen 
It is ‘ mon activité favorite …’ . L’activité - feminine noun, hence feminine adjectival agreement.
For completeness, the fact that ‘ le ski ‘ is masculine has no impact on the adjectival form here.
See attached lesson for usage of possessive adjectives immediately preceding nouns or other adjectives commencing with vowels or h mute.
https://www.wordreference.com/fren/activit%C3%A9 
 https://progress.lawlessfrench.com/revision/grammar/use-mon-not-ma-with-feminine-nouns-starting-with-a-vowel-or-mute-h-possessive-adjectives