I didnt choose "I don't like it" when Lena give Ian a footjob.So that is the reason.The footjob route in 12.3 isn't strictly limited to cuck path. It'll also trigger if you made Lena act dominant in Ch.11 prologue, by selecting option for her to ride Ian's face (and later didn't protest "I don't like it" when she opts to give Ian a footjob)
Thank you.