The process for translation is to "tokenize" a stream of characters into "tokens" like this:

"Hello Sarah, what time is it?"

<Hello><_Sarah><,><_what><_time><_is><_it><?>

Then the tokens are used for inference with a Transformer net. There are no guarantees that output will be consistent to even small changes in the input. The network, based on the data it was trained on/luck, has slightly different connections for the <_Sara> token than for the <_Sarah> token leading to different output.

Here's a video of some Linux YouTubers reviewing Argos Translate (https://github.com/argosopentech/argos-translate), the underlying translation library, and getting unexpected outputs: https://www.youtube.com/watch?v=geMs9dxl1N8