"Do you start playing soccer in July?"
Translation:¿Tú comienzas a practicar fútbol en julio?
It rejected "empiezas a jugar al fútbol en julio". There is nothing about "Do you start playing soccer in July?" that requires "usted". Reported 4 May 2018.
It might actually be the 'al' you have between jugar and fútbol that is tripping it up. I tried "Comienzas jugar fútbol en el julio" (forgot the 'a' and added an unneccesary 'el') and it marked me wrong saying I used the familiar tú form and should have used the formal usted form. I tried again with "Comienzas a jugar fútbol en julio" and was marked correct. It seems if there is a small minor error like an omitted or surplus 'a' or 'el' or something like that, for some reason it tells you the verb is wrong instead of what's actually wrong.