Dataflow gen 2 adds steps to functions causing the functions to not work properly when invoked

I am moving my queries from Datamart (preview), to Fabric. I have created a new Warehouse, and am adding Dataflow gen 2. 

I have some functions that are invoked by queries. The problem is, Power Query is adding extra steps to my functions, causing the functions to get data from API, and then deleting everything again....

The functions is invoked for a list of customer numbers, and the API returns invoice information, that is then added to my table.

All the columns in the function has column type added in the function:

When i publish the dataflow, there are som steps that are added, and the update is aborted.

From value and Remove Columns are added automatically. I delete these, publish, but they are added again.

On my queries, this results in the following error:

Once i delete the steps, the "Fx" logo is back on the functions in the left pane, and my flows work again, but only in the power query. Once i pulish, the steps are added back again, and it stops working