I know in the case of only "essere" as an auxiliary verb, the past participle should have agreement with gender or number of subject, but in this sentences there are no subjects in both two sentences and with the same auxiliary verb "avere" Once it has declension and agrees with object and another time it doesn't! Why participle here (lasciato) doesn't correspond with direct object in the case of gender
Ieri mi ha lasciato (without correspondence with "La macchina") di nuovo a piedi.
while in following sentence (descritta) it does?
Da come me l'ha descritta (correspondence with "la macchina della mia amica") credo che sia un'occasione.