Nulls & Blanks in Dataflow Linked Entities

Hi - I'm using a stage dataflow -> cleanse dataflow -> report dataflow structure. One thing I discovered early on is that in a linked entity, any null text values are converted to blank (=""). When doing a calculated column [newcolumn] off of one of these text fields, if I say:

if [column] = "" then [othercolumn] else [column]

This appears to work as expected in the PowerBI Dataflow query editor.

However, when I refresh the dataflow and the dataset connected to the dataflow, [newcolumn] will always equal [column] even where [column] = "". If I replace blanks in [column] with null and change my formula to:

if [column] = null then [othercolumn] else [column]

This works in PowerBI Dataflow query editor and in the dataset.

This is cumbersome. The linked entity is automatically replacing nulls with blanks, and to get my formula to work correctly I have to re-convert the blanks back to nulls.

Is this expected behaviour?