Even though I got it right, there is no translation into english given, so I'm guessing it translates to "we don't have a bathroom here" ?
You're right, the main answer is "We do not have a bathroom here."
As for that bug, I've not seen it on the English -> Polish course. I hope it's a one-off for you. I had something odd yesterday - it was a type what you hear with no audio :/ I put that down to dodgy wifi.
It happens on the "select the missing words" exercises. It tells you if you are correct without giving a translation. This is the case for all of these exercises.