Time changing randomly on Windows 7

The time keeps changing randomly on my PC. The operating system is Windows 7 Professional service pack 1 Time Zone: UTC Dublin, Edinburgh, Lisbon, London Time changed on March 29th 2020 as expected. Day Light Savings is checked.

Ran several tests that all started at 01:55 AM on 6th of April 2020.
Each test ran for 70 minutes outputting time and date every minute monitored via batch file and outputted to log file.

   @echo on
    set loop=0
    :loop
    rem echo Logged time = %time% %date%>> logtime.txt
    timeout 60
    set /a loop=%loop%+1 
    echo Logged time = %time% %date%>> logtime.txt
    if "%loop%"=="70" goto next
    goto loop
    :next
    echo  end time Logged time = %time% %dat

Results from testing time displayed just before and after time changed

Test 1 shows time changed by 1 hour 
Test1: Output should expect time 2:07:42 to change to 2:08:33
Logged time =  2:03:42.10 Mon 06/04/2020
Logged time =  2:04:42.11 Mon 06/04/2020
Logged time =  2:05:42.12 Mon 06/04/2020
Logged time =  2:06:42.13 Mon 06/04/2020
Logged time =  2:07:42.14 Mon 06/04/2020
Logged time =  **3:08**:33.61 Mon 06/04/2020
Logged time =  3:09:33.12 Mon 06/04/2020
Logged time =  3:10:33.13 Mon 06/04/2020

Test 2 shows time changed by 1 hour
Logged time =  2:46:59.13 Mon 06/04/2020
Logged time =  2:47:59.14 Mon 06/04/2020
Logged time =  2:48:59.15 Mon 06/04/2020
Logged time =  **3:49:27**.61 Mon 06/04/2020
Logged time =  3:50:10.82 Mon 06/04/2020

Test 3 shows time changed by 1 h
Logged time =  2:49:50.10 Mon 06/04/2020
Logged time =  2:50:50.10 Mon 06/04/2020
Logged time =  2:51:50.10 Mon 06/04/2020
Logged time =  **3:52:17**.66 Mon 06/04/2020
Logged time =  3:53:17.16 Mon 06/04/2020
Logged time =  3:54:17.16 Mon 06/04/2020

Not sure why the time is changing randomly by 1 hour, as it should have only changed by 1 minute. Need help to figure this out.

Regards, Chris