"I like colorful clothes."
Translation:Lubię kolorowe ubrania.
Doesn't "Lubię ubrania kolorowe" work, too? I could've sworn I've seen that word order in poems before.
The thing is, Polish has a (almost) free word order, so in this case you have 3!=6 different combinations, all of which are technically correct. However, in normal speech you would only use one of those - "Lubię kolorowe ubrania". Other combinations can be either used situationally to emphasise one of the words or are just plain weird.
Now the question is what do you expect to get from Duolingo. If you want it to prepare you to speak casually then it makes sense for it to mark weird-sounding word orders as incorrect. Unfortunately there doesn't seem to be 'technically correct, but...' option.
Also Duolingo is made by humans, and sometimes they just didn't add some correct translations. In this case reporting the error can help.
P.S. I'm talking not about this sentence, but in general.
in this sentence only "lubię kolorowe ubrania" is OK.
adjective after noun does not work here - colourful is a description, not a "kind of".