ModifyDate of Event Frames all get modified with security group changes

When someone makes changes to security groups (add, delete, etc) and these groups have global access to event frames in a database, end result is that all event frames get an identical modifydate for that time. We use this modifydate to detect any 'changes' to event frames for some downstream processing, end result is we cannot differentiate event frames that have truly been modified and thus have to process ALL event frames. Ideally a securtuy group change would not make any modifications to the event frame itself.