Why "Test run in Excel" shows "~" before some characters?

Hello together,

when I create a test run, and click "Run in Excel", codebeamer (v 2.1.0.0 with mysql) creates an Excel file.

Inside this Excel file, in the columns ACTION, EXPECTED RESULT, etc. some characters are prefixed with the "~" character.

For example my text in codebeamer test step is 

   set par_CP_voltage = 12V

   set par_CP_dutycycle = 50%

in the Excel file it will show up as

   set par~_CP~_voltage = 12V

   set par~_CP~_dutycycle = 50~%

This happens for at least the characters: _ ! # %

Does anybody know how to avoid this?

Thx in advance,

Philipp