The cutoff time indicates the last point in time that data from enrichment datasets (with time indices set) can be used for feature generation. Setting a cutoff time alone does not do anything, but if you also set a time index on an enrichment dataset, all rows whose time index value is greater than or equal to the cutoff time will be excluded. This is helpful in avoiding leakage for prediction problems.

E.g. cutoff time for one row is 2022-05-10. Nothing happens until a time index is set.