[Bug report] [Translate] Translation returns original input unchanged for specific sentences (e.g. EN → JA)

**Describe the bug**
When using ML Kit's on-device Translation API to translate specific English sentences into Japanese (or potentially other target languages), the API silently returns the original source string instead of a translated result. No error is thrown, and the OnSuccessListener fires normally — making it appear as though translation succeeded.

**Affected Input Example:**
```
Today, we received final client approval for the layout.
```
Translating this string from English (EN) to Japanese (JA) returns the exact input string unchanged.

**Additional Notes**

- No exception or failure callback is triggered — OnSuccessListener fires as if translation succeeded.
- The issue appears to be input-specific; other sentences translate correctly.
- Replacing/Removing trigger words (e.g. "client", "approval") produces correct translations.

**To Reproduce**
You can reproduce this using the [MLKit Quickstart Sample App](https://github.com/googlesamples/mlkit/tree/master/android/translate):

Clone the repo and open the android/translate sample in Android Studio.
Ensure the EN → JA translation model is downloaded on-device.
Input the following text into the translation field:

```
Today, we received final client approval for the layout.
```

Set source language to English and target language to Japanese.
Tap Translate.

**Expected behavior**

Expected Result:
A Japanese translation, e.g.:

```
本日、レイアウトについてクライアントから最終承認をいただきました。
```

Actual Result:
The original English string is returned unchanged:

```
Today, we received final client approval for the layout.
```

**SDK Info:**

- MlKit Translate [com.google.mlkit:translate:17.0.3]

**Smartphone:**
- Samsung S25 (can be reproduced on other models as well)