This is caused by the language settings. By default locale is not configured in BE docker container, but it's required (UTF-8) to be able to display the all special characters correctly.
It is required to install UTF-8 lang package in docker container.
For the installation update the Docker file of the application image(RMS server or BE application) and add below lines before build the image.
# Support: Install UTF-8 locale to be display Chinese characters correctly
RUN apt-get clean && apt-get -y update && apt-get install -y locales && locale-gen en_US.UTF-8
ENV LANG en_US.UTF-8
Attached is a sample Dockerfile used to build the RMS server image (BE base image: "com.tibco.be:5.5.0-1.00").