This is because - (minus or hyphen) is a special symbol/token in SharePoint search.
Special characters such as comma (","), semicolon (";"), colon (":"), underscore ("_"), minus ("-"), or forward slash ("/") are treated as white space. This is related to the tokenization process in SharePoint search query processing.
All the OOB values from Refinement web part works fine because they all converted to hex values. If you see them how they are sending to server when you refining, they all has hex values.
For example, if you convert
praveen-battula then it becomes ǂǂ7072617665656e2d62617474756c61
Whereas ǂǂ is the special two characters which tells SharePoint that it is hex value.
When it comes to your problem, I believe "Other Value" field is not converted to hex code (I need to test). If this is not working as expected in OOB web parts then it is a problem in SP product itself.