"This city is the capital of this planet."
Translation:yuQvam mon 'oH vengvam'e'.
There's only one accepted translation for this sentence and it's yuQvam mon 'oH vengvam'e' with a space between the two words, at least in the backend....
It sounds like a Duolingo bug to me, but one I haven't heard of before. If it happens to you again, could you take a screenshot and upload it somewhere, please? Then we can forward it to Duolingo developers.