Service incident - 19th of June 2026 - Guess correction not applied to fill-in-the-gap questions with hidden (alpha)numeric gaps

  lightbulb_outline Please note that this incident is ongoing. We will continue to share updates in this article.

All times in this document are recorded in UTC+2 (CEST).

Incident summary

An issue was identified where the guess correction was not applied to certain fill-in-the-gap questions. Specifically, this occurred when a fill-in-the-gap question contained hidden (alpha)numeric gaps.

Although these hidden gaps were not visible to students and could not be answered, their presence caused the system to exclude the question from guess correction calculations. As a result, questions that only contained answerable dropdown gaps for students could incorrectly receive no guess correction if hidden (alpha)numeric gaps were also present.

A fix for this issue was deployed on June 19, 2026, at 13:39. We are currently investigating the full impact of this issue. Schools with impacted assignments that have a scheduled publication and timeslot have already been informed.
 

Lead-up

On June 17, 2026, at 13:53, a user contacted support after noticing that guess correction was not being calculated for a fill-in-the-gap question.

The reported behaviour was investigated by the technical team. Initial analysis showed that certain questions containing only dropdown gaps did not receive guess correction, despite meeting the requirements for guess correction to be applied. 

Further investigation revealed that these questions also contained hidden (alpha)numeric gaps, which influenced the guess correction eligibility logic.
 

Fault

This issue has existed since the construction page of fill-in-the-gaps questions was updated on December 7th, 2025. As part of that update, removed gaps became restorable. Rather than being immediately deleted, removed gaps were retained in a hidden state within the question configuration until they were permanently deleted by a user. 

Fill-in-the-gap questions can contain multiple types of gaps, including dropdown gaps and (alpha)numeric gaps. When gaps are removed from a question, they are soft deleted and remain present in the underlying question configuration, while no longer being shown to students or being answerable. If these removed gaps are permanently deleted, they are fully removed from the question configuration.

The logic responsible for determining whether guess correction should be applied incorrectly took hidden (alpha)numeric gaps into account. When a hidden (alpha)numeric gap was present, the question was treated as containing (alpha)numeric gaps, even though students could only interact with dropdown gaps.

Because guess correction is not applied to questions containing answerable (alpha)numeric gaps, the presence of hidden (alpha)numeric gaps caused the system to incorrectly skip guess correction for the entire question.

As a result, fill-in-the-gap questions that should have received guess correction were calculated without it.
 

Impact

We are currently investigating the impact of this issue.

Initial analysis has confirmed that results have been affected. The full scope of impacted assignments and results is still being determined. 

The affected schools are being informed as impacted assignments are identified.
 

Detection

The issue was reported by a user via a support ticket. The technical team investigated the reported behaviour and identified the underlying cause.
 

Response

The support team forwarded the issue on June 17, 2026 at 14:55 to the technical team by creating a task to resolve the issue. 

On June 18, 2026 at 15:04, the technical team started investigating the issue. A fix for the issue was written, reviewed, and deployed on June 19, 2026 at 13:39. The team is continuing to investigate the full impact of the issue and identify all affected assignments and results.
 

Recovery

A fix was deployed on June 19, 2026, at 13:39 to ensure that hidden (alpha)numeric gaps no longer affect the application of guess correction for fill-in-the-gap questions.

Following the deployment, newly created results are no longer affected by this issue.

The impact analysis is still ongoing.
 

Timeline

The investigation is ongoing. A detailed timeline will be added once the incident has been resolved.
 

Reflection

A full reflection will be added once the incident has been fully resolved and the investigation into the root cause, impact, and corrective measures has been completed.