I had exactly the same problem as Nina. Thanks for the comment to make sure that it is the carbon dioxide flow from the resource folder. Anyway, I am using ecoinvent 3.4 and considered the following issue:
There are two carbon dioxide biogenic flows, one is called carbon dioxide (biogenic) and the other one is called carbon dioxide (biogenic-100yr). For the first one, the software does not consider the carbon uptake when I look on the LCIA- results. For the second one (100-yr), it is working.
--> Does it make any difference using the 100-yr flow? I would prefer taking the other one as that flow is also used in some other processes.
Thanks in advance for your response,