Kapacitor Join not Performing Full Outer Join

Question

I have a TICK script (shown below) with two queries, both performing groupBy on the same tag. The script then joins the two queries on that tag and specifies a full outer join with a fill of 'null'. However Kapacitor seems to be treating it as a inner join as shown by the stats (also below). The queries emit 33 and 32 points each and the join emits 32. Shouldn't a full outer join emit at least as many points as the query with the greater point count (33)? When I |log() the queries I'm able to identify the record that is dropped by the join - it was emitted by one query and not the other.

Any suggestions on how to further troubleshoot this?

TICK script:

var raw_event = batch
    |query('''select rsum from jsx.autogen.raw_event''')
           .period(1m)
           .every(1m)
           .offset(1h)
           .align()
           .groupBy('location')

var event_latency = batch
    |query('''select rsum from jsx.autogen.event_latency''')
           .period(1m)
           .every(1m)
           .offset(1h)
           .align()
           .groupBy('location', 'glocation')

raw_event
    |join(event_latency)
        .fill('null')
        .as('raw_event','event_latency')
        .on('location')
        .streamName('join_stream')
    |log()

Stats:

"node-stats": {
    "batch0": {
        "avg_exec_time_ns": 0,
        "collected": 65,
        "emitted": 0
     },
    "join4": {
         "avg_exec_time_ns": 11523,
         "collected": 65,
         "emitted": 32
     },
     "log5": {
          "avg_exec_time_ns": 0,
          "collected": 32,
          "emitted": 0
     },
     "query1": {
          "avg_exec_time_ns": 0,
          "batches_queried": 33,
          "collected": 33,
          "emitted": 33,
          "points_queried": 33,
          "query_errors": 0
     },
     "query2": {
           "avg_exec_time_ns": 0,
           "batches_queried": 32,
           "collected": 32,
           "emitted": 32,
           "points_queried": 32,
           "query_errors": 0
 }