Inappropriate name tag assumptions

So I caught a skeleton horse on bedrock for windows 10 and had a great name for him "Nightmare" was the name. Well I didnt get past the third letter and my game told me it was an inappropriate name. 

 

I understand the first three letters are also in a very vulgar word, but that was definitely not the word I was trying to name my horse. Why did your game assume thats what I was trying to name him without even giving me the option to finish spelling his name? This has to be a bug so I didnt know where else to report it.