[BUG] DeltatTableStreamWriter batch_function does not work without merge statement(?)

[IMC07]

Describe the bug

See screenshots; in one I create a merge statement in spark sql, in the other one I do not, instead I put the merge conditions in the output_mode_params. The latter does not seem to be writing any data to the target table, but also does not show an error.
I checked that the other variables are all the same: the DeltaTableReader is exactly the same, and I reset the checkpoints (/volumes) and my_target_table's before testing.

Steps to Reproduce

See screenshots.

Expected behavior

I expect the same result in my_target_table2 as I have in my_target_table1.

Screenshots

Environment

Databricks 15.4 LTS (includes Apache Spark 3.5.0, Scala 2.12)

Additional context

Applicable Stack Trace