The Duolingo software causes a number of problems for the Klingon course. And you have just discovered two of them.
One is that the system sometimes removes capitals from the middle of sentences and sometimes adds them at the beginning of sentences. Please try to be strict on yourself with the capitals, but be lenient on the system because sometimes the right answer will have the wrong caps.
The second one that you have discovered is that the system is very lenient with typos. A one letter difference, and sometimes even a two letter difference, will often be accepted as correct. The system is supposed to show you a notice that you have a typo, but it doesn't always show it to you and I know from my experience that when I see the green bar I hit enter before I even have a chance to read any notes it has for me. This typo leniency is a particular problem for Klingon because the "words" are often just three letters and very similar to each other, so getting one letter wrong is a big deal and can significantly change the meaning. There's a big difference between admiring Kahless and killing Kahless!