I think Michael had a very relevant point here and I am surprised no one reacted since.
At first I thought Lingvist was great because it seemed to also teach grammar which most other apps don't do.
But the sentences for each word are so often the same that I can more efficiently answer them by recalling the correct sentence from the last time I saw it than by understanding why a particular ending is correct and how it is formed.
I can look up conjugation or declination tables in the app where they are available, which is good, but I found that this requires discipline since the primary incentive is to answer many questions quickly and plain memorization works better for that.
This way Lingvist tells me I am progressing quickly when in reality I am stuck as soon as real life situations require that I switch personal pronouns or the grammatical time of a sentence.
I see no other way to fix this outside of providing several different sentences for each word which would quickly make learning structure the more efficient process to answering cards.
Your total learning success metric will suffer, but it would more accurately reflect real learning.