The exact quote is here:
This is by no means the full extent of the issues we identified within the files in our sample; it represents the tip of the iceberg. We also saw:
• A further 18 ‘borderline’ cases. In these cases, there was not enough evidence to conclude that the Labour Party was legally responsible for the conduct of the individual. These were people such as local councillors, local election candidates and Constituency Labour Party office holders.
• In many more files, evidence of antisemitic conduct by an ‘ordinary’ member of the Labour Party. These members did not hold any office or role, therefore the Labour Party could not be held directly responsible for their conduct under the Equality Act 2010.

In light of our position as a regulator, we only made findings of unlawful conduct in cases that were sufficiently clear-cut, in Equality Act 2010 and Human Rights Act 1998 terms. We explain this in Chapter 3


So they saw cases, but restricted themselves to ones that were 'clear cut' and for which the party was legally responsible.