In the Finnish translation of the app, you use the word "lykätä" as translation for "postpone". The correct form is "lykkää".
"Lykkää" is the grammatically correct version of the word "lykätä" when used in a button, as "lykätä" is the nominative form ("to postpone") and "lykkää" is the imperative form ("App, I want you to postpone this.").
Thank you for pointing this out. We will share it with our department of translation. In the meantime, if there is anything else that we can do for you, please let us know at firstname.lastname@example.org