This is an issue with Relog.exe. So we have to work around it.

Repro Steps:

1. Import a .BLG file in a database

   C:\Windows\System32>relog "c:\temp\sqldiag.blg" -f sql -o "SQL:sqldefaultinstance!TestRelog"

   Input
   ----------------
   File(s):
        c:\temp\SQLDIAG.BLG (Binary)
   
   Begin:    6/3/2020 16:18:18
   End:      6/3/2020 16:19:29
   Samples:  15
   
   100.00%
   
   

   Output
   ----------------
   File:     SQL:sqldefaultinstance!TestRelog
   
   Begin:    6/3/2020 16:18:18
   End:      6/3/2020 16:19:29
   Samples:  15
   
   The command completed successfully.
   

2. Connect to the database server and run the following queries

   SELECT TOP (5) 
         [CounterDateTime]
         ,[CounterValue]
         ,[FirstValueA]
         ,[FirstValueB]
         ,[SecondValueA]
         ,[SecondValueB]
     FROM [TestRelog].[dbo].[CounterData]

   Result:

   CounterDateTime          CounterValue           FirstValueA FirstValueB SecondValueA SecondValueB
   ------------------------ ---------------------- ----------- ----------- ------------ ------------
   2020-06-03 16:18:18.970  0                      0           0           789406234    246
   2020-06-03 16:18:24.016  0                      0           0           839873505    246
   2020-06-03 16:18:29.065  0                      0           0           890361981    246
   2020-06-03 16:18:34.116  0                      0           0           940875170    246
   2020-06-03 16:18:39.163  0                      0           0           991350448    246
   
   (5 rows affected)
   

3. Take a value from above output and try to search for it. THE QUERY RETURNS NO RESULTS BECAUSE THE DATA IS INVALID

 select top (5) CounterDateTime 
 from counterdata
 where CounterDateTime = '2020-06-03 16:18:18.970'
 go

 Result: 
 
 CounterDateTime
 ------------------------
 
 (0 rows affected)

4. Attempt conversion - CONVERSION TO DATETIME FAILS BECAUSE THE DATA IS INVALID DateTime

   select cast(CounterDateTime as datetime)
   from counterdata
   go

   Result: 
   
   -----------------------
   Msg 241, Level 16, State 1, Line 15
   Conversion failed when converting date and/or time from character string.
   

5. Analysis shows that the last character is null/0 and should be 0x20

   select top (5)
   ASCII(substring(CounterDateTime,24,1)) LastCharacter
   ,CounterDateTime
   from counterdata

   Result: 
   
   LastCharacter CounterDateTime
   ------------- ------------------------
   0             2020-06-03 16:18:18.970 
   0             2020-06-03 16:18:24.016 
   0             2020-06-03 16:18:29.065 
   0             2020-06-03 16:18:34.116 
   0             2020-06-03 16:18:39.163 
   
   (5 rows affected)
   

6. Manual fix (workaround) which shows the root cause. Fix the data by running this update.

   --update the last character to 0x20
   update counterdata set CounterDateTime = 
   substring(CounterDateTime, 1,23) + char(32) 
   from counterdata

7. Now queries work

   select top (5) CounterDateTime 
   from counterdata
   where CounterDateTime = '2020-06-03 16:18:18.970'
   go

   CounterDateTime
   ------------------------
   2020-06-03 16:18:18.970 
   2020-06-03 16:18:18.970 
   2020-06-03 16:18:18.970 
   2020-06-03 16:18:18.970 
   2020-06-03 16:18:18.970 
   
   (5 rows affected)
   

   select cast(CounterDateTime as datetime)
   from counterdata
   go

   -----------------------
   2020-06-03 16:18:18.970
   2020-06-03 16:18:24.017
   2020-06-03 16:18:29.067
   2020-06-03 16:18:34.117
   2020-06-03 16:18:39.163
   2020-06-03 16:18:44.213