You could try using an intermediary Damage and Apply Behaviour effects, in conjunction with the Unit Takes Damage event. While it's not as straight-forward as you could hope for, it'd be the first thing that springs to mind. The only issue I can think of would be that you probably wouldn't be able to find out who applied the Behavior apart from at initial application (unless you want store the 'casting' unit in a Bank, using the Behaviour [if possible] and the target unit as your keys)
This tutorial explains it in greater detail, but you should be able to 'catch' the application of the behavior, along with who applied it (assuming you set up the Effects properly).
Well that'll work though it's kind of annoying to have to use set effects for every attribute modding effect :thdown: Hope they add something like caster of behavior at least for the attribute change event.
I do know this - xenforo dropped the ball by not keeping the vbulletin reputation comments as a feature. The loss of the Reputation comments data when we switched to Xenforo really was the death knell for the site when it came to all the users that left. I know I missed it so much and I got way less interested in the site when that feature was gone and I run the site.
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory