The one that tells you that you cannot vote on your own post uses German even though the interface is in English. You can notice that because “An error occurred” and the buttons below are all in English.
The message that you cannot undo your vote anymore works partly. When you click the same chevron you used for voting, so you are trying to add an upvote when you already added an upvote or add a downvote when you already added a downvote, it works. However, when you change your mind and try to use the other button, it fails.
The “you are only allowed to vote once” message is a little difficult to trigger. You need to wait until you are no longer allowed to change your vote. Then, first try to change your vote and then try the other button.
