Item Reclass Journal in code to change Lot and Bin

Hello

I am creating a warehouse reclass jnl in code to reclass an item to a new lot and move it to a diff bin.
If I try and post the journal within the code I only get a ILEs created and no warehouse entries (also I get my line left in the reclass journal batch!); however if I comment out the line to do the post bit (CODEUNIT.RUN(CODEUNIT::"Item Jnl.-Post Line",ItemJnlLine) and I go to the reclass batch page and post it manually I get ILEs and warehouse entries correctly.

Anyone seen something this before?
What am I missing?