Sometimes the "Alternative Translations" feature of Kagi Translate will show the descriptions for the alternate translations in the target language, rending a non-native speaker at a loss for what the changes might be.
For the translation below, I got JA descriptions using both standard and best qualities for all 4 alternate translations.
Long but casual prompt example

On a shorter prompt, this one, I got the source language descriptions as I would have expected.
Short Prompt Example

Again on a longer translation I get descriptions in the target language (borrowed the text from a public Cloudflare postmortem, not anything confidential). This happened for both Best and Standard.
Cloudflare Postmortem Translation Example

Going with even one of those two paragraphs still produced the target language descriptions. However, going with a very short translation seems to work as intended. This succeeded with both Standard and Best.
Short Translation Example

Hopefully thats enough examples.
The description of alternative translations should always be in the source language so a non-speaker can identify what the differences are between the translations.