For ゆ I always have to mark it as “Got It” manually and can almost never get it to recognize. I think for Hiragana, the recognition is way too strict. I wish there was a non-strict option for Kana.
I’m using the Android App 3.3.5 (300317).
Some other ones are difficult as well, but this one is definitely the worst.
Also, in the Skritter Japanese app it says 100% for Hiragana, but on the website, it says I’ve only done about 30%. So something is out-of-sync there.