The card Fracture have a translation Mistake.
In french it's written : Destroy target artifact, CREATURE or planeswalker.

In reality, the card can't destroy CREATURE but enchantement.

Japanese translation is missing the "other" wording, to indicate that it does not count when the card itself is modified.

Dire wolf Prowler's activate ability 1R in Japanese,but correcting cost is 1G

The Japanese version of arborea pegasus' ability says +2/+2, but it actually only gives +1/+1 (modifying the creature next to it)

La carte affiche "détruisez l'artefact, la {créature} ou le planeswalker ciblé" mais une fois lancé le jeu demande de choisir, un artefact, un {enchantement} ou un planeswalker

Metallic Mimic can be "Any" creature type. I can't pick "Shrine" as a creature type?

I have created an app that allowed to translate the client prior to version 2021.9.0.3880.888241. Unfortunately that version has more rigorous checksum checks and Arena is rendered unusable in the process. Modified files are deleted but original ones are not being downloaded.

My project mtgpopolsku.pl was used by many players that don't know any of available languages. My voluntary (and completely free) work was beneficial to you and I even have permission to do so.

Please add a way to translate the interface and card database and to add new language to drop-down menu in settings.

Text of Split Cards is not displayed properly in Korean Language.

Splitcardartifact

秩父の学部長オーガスタをコントロールした状態で攻撃した際、秩序の学部長オーガスタの能力が誘発しますが、その際『あなたがコントロールしていてタップ状態である望む数のクリーチャーをタップしてください』と、正しくない説明文が表示され、正常なテキストでのゲーム環境となりませんでしたため、750ジェム、または5000ゴールドの補償を請求します。

When upgrading Rogue Class to Level 3, the text of the card states "CARDNAME" instead of Rogue Class. This error does not seem to appear at any other time when examining the card.

In MTG Arena, I found a wrong text in Japanese version of Teferi, Who Slows the Sunset. The text says untap and tap opponent's permanent.

予備の短剣の生贄時能力の説明文が文字化けしています。

The french translation of Cosmos Elexir says "you gain 1 life" instead of "you gain 2 life".

終異種、魔技のテキストが文字化けしています。

The German translation from wingshield agent is wrong?
There is not the word "other" in the german card text.