NJ, Sue Gray's terms of reference include the following,
"The primary purpose will be to establish swiftly a general understanding of the nature of the gatherings, including attendance, the setting and the purpose, with reference to adherence to the guidance in place at the time.
If required, the investigations will establish whether individual disciplinary action is warranted.
The work will be undertaken by officials in the Cabinet Office at the direction of the Cabinet Secretary, with support from the Government Legal Department.
The team will have access to all relevant records, and be able to speak to members of staff. As with all internal investigations, if during the course of the work any evidence emerges of behaviour that is potentially a criminal offence, the matter will be referred to the police and the Cabinet Office’s work may be paused. Matters relating to adherence to the law are properly for the police to investigate and the Cabinet Office will liaise with them as appropriate.
Any matters relating to the conduct of Ministers should follow the process set out in the Ministerial Code in the normal way."
As she is also looking at internal disciplinary matters, it is not unreasonable for her to consider and then comment upon any perceived culture or circumstances leading to those disciplinary matters.