Not enough time!
The timing practice in Japanese is too difficult. Duolingo has always awarded more time based on sentence's length, but looks like something is off with Japanese. Probably has to do with the fact that you cannot really say that one Japanese character is of equal weight as one latin character.
I'm a pretty fast typer, and I've already been on N4/N3 for a while now, and Japanese timed practices seem almost impossible if I make more than two mistakes.
Happens to anyone else?
To be clear, I'm actually perfectly fine with this: I don't think that it should be easy to complete timed practice. Duolingo has gotten too soft this year and I'd really like a challange to complete timed practice. But I have a feeling that this was not team's intention as it only happens with Japanese. The rest is still fairly simple since after answering 4-5 question in a row correctly you get to having 1:30 time left which is a large enough buffer to screw up a lof of questions.
It seems that this is a pretty common experience. It gets easier if you know the EXACT words and word order that they will accept and increase your Japanese typing speed to 200wpm.