upsert data into table,'select' result is correct, but 'scan' find an odd data

[hnucsbjd]

phoenix version :phoenix-2.2.2-install,UPSERT INTO VALUES('row1','1','a') to a table,'select' is correct, but 'scan' find an odd data:' row1 column=A:_0, timestamp=1392107355805, value= ' ,the data is unnecessary?

phoenix-2.2.2-install/bin$ ./sqlline.sh localhost
0: jdbc:phoenix:localhost> CREATE TABLE TEST(pk VARCHAR NOT NULL PRIMARY KEY, a.col VARCHAR(1),col2 VARCHAR(1));
0: jdbc:phoenix:localhost> UPSERT INTO TEST(pk,a.col,col2) VALUES('row1','1','a');
0: jdbc:phoenix:localhost> select * from TEST;
+------------+------------+------------+
| PK | COL | COL2 |
+------------+------------+------------+
| row1 | 1 | a |
+------------+------------+------------+

hbase(main):002:0> scan 'TEST'
ROW COLUMN+CELL
row1 column=A:COL, timestamp=1392107355805, value=1
row1 column=A:_0, timestamp=1392107355805, value=
row1 column=_0:COL2, timestamp=1392107355805, value=a
1 row(s) in 0.1350 seconds