Stream-stream LeftOuter join is not supported without a watermark in the join keys

Question

I have the bewlow code that fails when Im attampting to do the stream stream left outer joins.

@dlt.view
def vw_ix_f_activity_gold():
    return (
        spark.readStream
        .option("readChangeFeed", "true")
        .table("lakehouse_poc.poc_streaming.activity_silver")
        .alias("ACT")
        
        # Join with Oracle Activity Data
        .join(
            spark.readStream.table("lakehouse_poc.poc_streaming.ix_d_activity_gold")
            .withWatermark("_fivetran_synced", "5 seconds")
            .alias("DAC"),
            F.col("ACT.activity_seq") == F.col("DAC.BK_activity_seq"),
            "left"
        )
        # Select and rename columns
        .select(
            ...
    )

dlt.create_streaming_table(
    name = "ix_f_activity_gold",
)

dlt.apply_changes(
    target = "ix_f_activity_gold",
    source = "vw_ix_f_activity_gold",
    keys = ["BK_activity_seq"],
    sequence_by = "_fivetran_synced",
    stored_as_scd_type = 1
)

not sure why this would have failed, i do have the watermarks. Do I also need to mention in apply_changes part too?