Issues with looped pipes

[gitfeldhase]

It seems that the optimization process has issues if there is something like a roundabout or a "loop" as presented in the attached picture.

If there are no other consumers connected to these lines I do not get a successful run and get the following error which seems to be from pyomo.

No value for uninitialized NumericValue object InvestmentFlow.invest[infrastructure_heat_pipe-typ-A_forks-109-forks-108,infrastructure_heat_bus_forks-108]

Is this a known issue and any recommendations how to fix it with preprocessing?

Best regards

[joroeder]

So far, I had no problems with looped metworks. I am currently out of office. If you post the example, I could have a deeper look when I am back in office in the second half of February.