The field mapping looks fine. It's pulling in all the columns and they're tied to the correct dataset. To build the model, I ran the entire process manually and then pulled in the tools using history so that the field mapping and other settings are pulled into the model builder tool.
I was facing issues with the gdb location for the intermediate data so I put in %scratchGDB%. The datasets in the field mapping show up as: C:Users\myuser\AppData\Local\Tmp\ArcGISProTemp###\hashes\scratch.gdb\Properties
Do you think this could be causing the issue?