Grib1 Time Coordinates incorrectly constructed

[lesserwhirls]

Attached is a grib1 file with four records of the same variable on the same grid. They differ by the following in the PDS:

Record 1 to 2:
Compare Pds
  18 :   1 !=  14
  20 :   0 !=   1
  21 :   0 !=  10

Record 1 to 3:
Compare Pds
  19 :   0 !=   1

Record 1 to 4:
Compare Pds
  18 :   1 !=  14
  20 :   0 !=   3
  21 :   0 !=  10

That is, only the time information varies. The relevant PDS octets look like the following:

Record 1:

13-17           Reference Time : 2017-08-04T00:00:00Z
18                  Time Units : (1) 1 Hour
19                 Time 1 (P1) : 0
20                 Time 2 (P2) : 0
21        Time Range Indicator : (0) Uninitialized analysis / image product / forecast product valid for RT + P1

Time Value: 2017-08-04T00:00:00Z

Record 2:

13-17           Reference Time : 2017-08-04T00:00:00Z
18                  Time Units : (14) 30 Minute
19                 Time 1 (P1) : 0
20                 Time 2 (P2) : 1
21        Time Range Indicator : (10) product valid at RT + P1, P1 two digits value 18, 19

http:https://www.nco.ncep.noaa.gov/pmb/docs/on388/table5.html
P1 occupies octets 10 and 20 -> 01
Time Value: 2017-08-04T00:30:00Z

Record 3:

13-17           Reference Time : 2017-08-04T00:00:00Z
18                  Time Units : (1) 1 Hour
19                 Time 1 (P1) : 1
20                 Time 2 (P2) : 0
21        Time Range Indicator : (0) Uninitialized analysis / image product / forecast product valid for RT + P1

Time Value: 2017-08-04T01:00:00Z

Record 4:

13-17           Reference Time : 2017-08-04T00:00:00Z
18                  Time Units : (14) 30 Minute
19                 Time 1 (P1) : 0
20                 Time 2 (P2) : 3
21        Time Range Indicator : (10) product valid at RT + P1, P1 two digits value 18, 19

Time Value: 2017-08-04T01:30:00Z

Using toolsUI and the IOSP -> Grib1Collection interface, all four records show up, and the valid forecast times are correct.

However, if we read the grid through the toolsUI CoordSys interface, only three time values are constructed:

Hour since 2017-08-04T00:00:00Z
time =
  {0.0, 1.0, 2.0}

 2017-08-04T00:00:00Z
 2017-08-04T01:00:00Z
 2017-08-04T02:00:00Z

Comparing the actual values in the grid, I can see that the first time coordinate is associated with Record 1, the second with Record 3, and the third with Record 4 - record 2 is skipped.

Both 4.6.x and 5.0 show this behavior.

timeUnitChangeFourRecords.grib1.zip