There was a bug in Cash Flow reports which was fixed in 2017.3.
As I experienced the bug it was a simple case of the cash flow being shown as a negative (red) when it should have been the opposite. Just maybe, if you have a more complex situation it could be related to the same bug.
If you are already using 2017.3 then just ignore this suggestion,
The bug you mention is not the issue, the information in the category is not getting reported at all. If it was negative then I could easily change that as I copied all the data into excel for analysis.
The screenshots show clearly that even though I selected to show these categories, the mentioned one is not shown. It is though reflected in the account on the report
I would love to always use the latest version of MD, but they don’t tell you when a new version is available, so I tend to stumble across releases rather than informed. I have just upgraded to the latest version is 2017.4.