The pronunciation is off for that word in this case. We get what we pay for--DL is free. The problem of pronunciation is consistent in DL languages but is worse for some and better with other languages. It's a frequent topic in Greek but the moderators help us a lot with the problem and point out where we can have a human pronunciation. An additional matter is the stage in which the language in DL is up and running. The beta version of the Arabic has many, many problems with pronunciation, which compounds the problem that Standard Spoken Arabic is artificial in relation to the many pronunciations of Arabic globally. As a beginner to Arabic, I'm just trying to gain a foothold. But with Spanish, the pronunciation of cómoda is displayed by the accent, no?

Still not fixed 23 April 2018 and reported again.

Because not all words are reflexive. Reflexive verbs refer to oneself. So Ponerse means "to put on to oneself", and it is reflexive, as opposed to Poner, which means "to put" and isn't reflexive. To conjugate Poner for nosotros, we would simply say Ponemos, but to conjugate Ponerse, we say Nos Ponemos.

It is also a synonym for "clothes" and a valid translation for ropa.

I believe "nuestra" is "our." So it should be "Siempre nos ponemos nuestra ropas cómodas. "

No. It is accepted is some phrases, in others, it isn't. You should report it, I guess.

It's a great question. Some languages use collective singular, including English (will you get your hair cut? not hairs), for some things but not others. Here's a discussion of this matter: https://forum.duolingo.com/comment/22679172