Script server fails during reading of large unicode output

[bugy]

When reading 17Kb file, with russian text, script server failed with the following error:

2019-06-23 23:12:14,549 [script_server.process_pty.ERROR] Failed to read script output
Traceback (most recent call last):
  File ".../DEV/github/script-server/src/execution/process_pty.py", line 113, in pipe_process_output
    output_text = data.decode(self.encoding)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xd0 in position 933: unexpected end of data

This error is random, can happen in different positions of the file, or can even succeed, if a file is not very large.
This happens in terminal (pty) mode.