Report incomplete
The court decision put special emphasis on the way to the home office only being insured if it can be proven that the insured person was indeed traveling for the first time of the day into the home office, which must be a dedicated room separated from the rest of the dwelling (in this case being on a different level). That first walk is unavoidable, and thus insured, coffee and bathroom breaks probably won't be.
A brief report of the decision by the court: https://www.bsg.bund.de/SharedDocs/Verhandlungen/DE/2021/2021_12_08_B_02_U_04_21_R.html