To reproduce:

1. Download attached "testJapaneseText.zip" project and open in Unity
2. Open "MainScene" scene
3. Build for iOS
4. Deploy the Xcode project to the iOS device
5. When App is opened press on "Output long Japanese text" button
6. Take a look at the output in Xcode.

Expected result: You will see only a long Japanese/Korean string of text
Actual result: You will see a long Japanese/Korean string of text and between this text, there will be characters as \343 and \201

Notes:
- This issue is reproducible only on iOS
- On Unity Editor, Standalone (Mono and IL2CPP) and Android (Mono and IL2CPP) everything works as Expected
- Other Japanese words also result in the same issue
- Trying to print this string to UI results Expected results so it is printed wrong on Xcode console
- This was discovered when attempting to output a long JSON file containing Japanese text. The \343 makes it impossible to send JSON to the Server and Customer have been unable to escape the character(s) either
- Images for Reference are attached in Comments section

Tested with:
- iPhone 7, iOS: 10.2 - Reproduced
- iPhone 8 Plus, iOS: 12.2 - Reproduced
- VLNQA00150, Samsung Galaxy S9 (SM-G960U), Android 9, CPU: Snapdragon 845 SDM845, GPU: Adreno (TM) 630 - Not Reproduced
- VLNQA00173, Xiaomi Redmi 6 Pro (Redmi 6 Pro), Android 9, CPU: Snapdragon 625 MSM8953, GPU: Adreno (TM) 506 - Not Reproduced

Reproduced on Unity 2017.4.0f1, 2017.4.31f1, 2018.3.14f1, 2018.4.5f1, 2019.1.13f1, 2019.2.0f1 and 2019.3.0a11