Power BI dataflow null comparison failure

[stewartfiserv]

I think I have found a bug in Power BI Dataflows that does not occur in Power BI Desktop.  It has to do with null comparisons.  I have a step in my flow shown below:

Table.TransformColumns(AddedPrimaryKey, {{"Parent Id", each if _ <> null then Number.FromText(Text.End(_, Text.Length(_)-2)) else null, Int32.Type}})

The resulting table shows that the Parent Id field has null values.  You can see them.  

However, when I try to filter records where [Parent Id] = null, I do not get any matches.  It's as if the null value retruned by Transform Columns is not a normal null value.  If I run the same filter prior to this step if finds records. 

Any idea what I am doing wrong in this step?  Is this really a bug?

[stewartfiserv]

I was able to fix the issue by splitting the step:

    TransformedParentId = Table.TransformColumns(AddedPrimaryKey, {{"Parent Id", each if _ = null then _ else Number.FromText(Text.End(_, Text.Length(_)-2))}}),
    ChangedParentIdColumnType = Table.TransformColumnTypes(TransformedParentId, {{"Parent Id", Int64.Type}}),

Is this a bug?