"Did you guys already walk along the beach?"

This is like many of the new exercises where Duo seems to lack internal communication. The test page counted me wrong and wrote "You used the ellos/ellas/ustedes form "caminaron" instead of the vosotros/vosotras form "caminasteis", and then wrote "¿ ya caminasteis por la playa? as the correct answer. This page has ¿Ustedes ya caminaron por la playa? as the correct answer. My answer was "ya caminaron ustedes por la playa".

Is this word order OK? - "ya caminaron ustedes por la playa".

This page counted me wrong and wrote "You used the ellos/ellas/ustedes form "caminaron" instead of the vosotros/vosotras form "caminasteis", and then wrote "¿ ya caminasteis por la playa? as the correct answer. This page has ¿Ustedes ya caminaron por la playa? as the correct answer. My answer was "ya caminaron ustedes por la playa".