Shell integration displays invalid characters on linux terminals

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• iTerm2 version: latest
• OS version: Ubuntu 16.10 / centos

Detailed steps to reproduce the problem:

1. Install shell integrations on linux server (CentoOS 6)
2. shell into server from any terminal emulator on Ubuntu 16.10

What happened: unsupported characters cause the altered prompt to be invalid escaped ansi codes (see screenshot)

What should have happened: prompt should be displayed normally with ansii characters escaped