French language Q&A Forum

"It is green" still gets "il est vert" marked wrong, despite the fact that it appears to refer to a specific item (as opposed to using "c'est vert," the preferred answer, which would indicate something more general--despite no indication of such in the sentence). Tired of having my score set back (I had to use up most of my free quizzes for the month to make up for this). Please fix. Would also be nice to have the "report it" button on the page that people seem to say exists but which I have never seen.

https://progress.lawlessfrench.com/my-languages/french/tests/results/15218594/system

The first sentence,  "il faut vraiment que l'on discute de ta mère"  is the contraction  l'on for "le" or "la" ?  I still don't get why it is even needed.  Would it not work to say, "...qu'on disute de ta mère"  which then maps to English as "that we discuss about your mother". 
I'm guessing that it's a direct object pronoun, but then why isn't "de ta mére"  the object of the sentence?

At the beginning of the second sentence the word "BASTIEN" is in the text, but it is not in the audio. All of the other sentences have the characters' name in both the text & the audio. 

Hi, in the line “nous avons développé des intérêts communs” I believe I’m hearing a short connecting word/syllable between “intérêts” and “communs”. Am I imagining this?

I thought I’d sorted this out already but evidently not. I believe that the answer I gave in the heading is, according to the lecture notes, correct. Correction welcome. So why was it marked wrong and the correct answer given as “je suis avec cinq minutes d’avance”? I’m fine with this answer too but why was my answer marked as incorrect?