Exporting feature classes that contain both thousands of features and text fields with Cyrillic values to Excel format generates corrupted outputs or missing Cyrillic values in the output.
Issue is due to problem in xlwt, to patch xlwt at Pro 1.3
1. open 'python command prompt'
2. run this command "conda update xlwt" to upgrade to xlwt version 1.1.2 (or greater)
The 1.4 release of ArcGIS Pro will ship with xlwt version 1.1.2 (or greater).