Sunday-question: Learning Dhamma at working time, on other recource
Bad kamma. The Buddha said:


  The servants and employees thus ministered to as the Nadir by their
  master show their compassion to him in five ways:
  
  (i) they rise before him, (ii) they go to sleep after him, (iii) they
  take only what is given, (iv) they perform their duties well, (v) they
  uphold his good name and fame.
  
  DN 31


But if a person is self-employed and their work day does not require 8 hours work per day then its no problem. If the self-employed person has free time during their work day in their office then discussing Dhamma is good kamma.