You have nothing to worry about. This is an issue with the score displaying incorrectly, and not an indication that your assessment was scored incorrectly.
Despite this, we understand that it can be unsettling to see your score change, so our developers are in the process of fixing this bug.
It is also worth noting that the points are just a tally that we use to motivate you through the assessment. There is no link whatsoever between your ‘score’ and your likelihood of progressing. You can learn more about the end score here.