Disable Delta format to read as Parquet you need to set to false the following Spark settings:

>> SET spark.databricks.delta.formatCheck.enabled=false

OR

>> spark.conf.set("spark.databricks.delta.formatCheck.enabled", "false")

its not recommended to read the delta table directory using the read.parquet because the delta table directory can always possibly have in-active files which are to be cleaned up by vacuum.