Negative number of Unknown words

We chatted with one my friend, and I occasionally said that I am learning Japanese. She wants to learn Japanese for years, so she registered at LingQ and asked me what to do. As usual I advised her to learn hiragana first. So, I opened Library and searched for Emma’s “Hiragana drill” collection. When I opened it I saw

あいうえお・かきくけこ 0:44 Advanced 2 5 (19%)
さしすせそ・たちつてと 1:00 Advanced 2 3 (9%)
なにぬねの・はひふへほ 1:09 Advanced 2 -1 (-3%)
まみむめも・やゆよ 0:46 Advanced 2 4 (12%)
らりるれろ・わをん 0:49 Advanced 2 -5 (-16%)
がぎぐげご・ざじずぜぞ 0:54 Advanced 2 -3 (-8%)
だぢづでど・ばびぶべぼ 1:00 Advanced 2 -5 (-13%)
ぱぴぷぺぽ・きゃきゅきょ・ぎゃぎゅぎょ 1:12 Advanced 2 -1 (-2%)
しゃしゅしょ・じゃじゅじょ・ちゃちゅちょ 1:04 Advanced 2 -3 (-7%)
にゃにゅにょ・ひゃひゅひょ・びゃびゅびょ・ぴゃぴゅぴょ 1:14 Advanced 2 8 (19%)

As you see some lessons have negative number of Unknown words :)) I suppose it because I have learnt not only words from this lesson, but phrases too.

Hi Rasana,

That is quite weird. I noticed that I, too, had some negative new words the other day for certain lessons in the Japanese library. I took one of these lessons and it is still showing up with negative new words for me but I can’t find any others in the library now. I will look into this further but it may have been a temporary problem.