I’ve just done a classic review on the new beta version, and it really wasn’t happy with “tan … como” and I don’t know why. I was just given building blocks to select which were basically “tan” “como” “…” “?” “¿” and maybe other unrelated words. So I wasn’t even typing the answer, just clicking the blocks, and it went orange as if I was wrong every single time (it kept giving me the same question to try again and I didn’t get it right until I got it as a listening exercise and chould just choose the one that SAID “tan … como”. I really don’t know what it wanted, and couldn’t have added any spaces or anything, the words were spelt in the blocks for me so I wasn’t spelling them wrong. I tried “tan … como” “tan como” “tan … como …”. Oh wait, maybe they wanted “… tan como” I don’t know, all I know is that “tan … como” is one of my dificult words now 
I’ve moved your post to the course’s officiai thread.