title_body: Why does my coffee at work have a paper/wood flavor?
upvoted_answer: Since most of your variables above have been addressed and matched. Below are an additional few i could think of -
  
  a) Servicing of equipment. At least descalling once per month depending on how often machine gets used.
  
  b) Someone at work "serviced" you machine with a strong dose of descaller, or didnt flush the system 3 times for both group head and steam wand. It is probable you are tasting descaller. To prevent descaller taste, use food grade coffee descaller recommended for your machine, any other chemical product maybe too strong and leave a lasting taste like CLR, vinegar etc.